Septic System Design & Septic Permit Drawings

Our expert septic system designers have extensive experience in designing onsite septic systems and preparing septic permit drawings in Ontario where properties in rural areas rely upon onsite septic systems for their sewage disposal. 

Our experienced and competent professional engineers licensed in Ontario specializing in septic systems, design a variety of advanced, innovative, predictable, permanent, robust, cost-effective, compact, low energy, low maintenance, visually subtle, and efficient onsite septic systems for off-sewer developments in Ontario.

Our septic system designs and the septic permit drawings meet the requirements of the Ontario Building Code and the Ministry of the Environment and offer the most affordable, long-lasting site-specific septic system design. Inappropriate septic system design, bad construction practices, or poor maintenance can all lead to septic system failure.

The two main factors that dictate the septic system design are the maximum amount of sewage that the building could produce daily, and soil/site conditions. Geotechnical investigation including proper soil testing ensures the septic system design meets the specific requirements of a site. Enlisting the help of a qualified and registered professional engineering firm is a key element to the successful septic system design. Our licensed professional engineers design onsite septic systems that will work best for the property based on the specific site-specific characteristics including

• Soil conditions (percolation rate, soil type, and depth)
• Height of groundwater table and bedrock
• Nature of the wastewater produced· Sewage flow per da

The Municipal Building Department or Health Unit, and if applicable a Conservation Authority examines septic system design and approves septic permit applications, issues septic permits for the construction of septic systems, and does inspections for septic systems regulated under Part 8 of the Ontario Building Code. The Municipal Officials regulate the design, construction, and approval of septic systems with a design capacity of less than 10,000 litres per day on one lot. The rate at which the wastewater will be absorbed into the soil is called a "T" time. "T" time is equal to the number of minutes it takes for the water level to drop per cm in a water-filled hole in the receiving soil. In sandy soil, a typical T time is less than 10 (meaning it took less than 10 minutes for the water level to drop 1 cm in the water-filled hole). But in sandy loam soil, the T time could be 20 or more because the smaller soil particles are slowing the rate of absorption. The worst soil though is clay where the T time is typically well over 50 because clay particles are so fine and tightly packed. Once the maximum amount of wastewater that the building could produce on a daily basis (Daily Sewage Flow) and the "T" time are identified, we can design the septic system accordingly. Each type of septic system then has a different equation to be used to design the septic system. 

Ontario Building Code Design Standards for Designing a Septic System

General Requirements for Septic Design

Site Evaluation

(1) A site evaluation shall be conducted on every site where a new sewage system is to be designed.

(2) The percolation time for the septic design shall be determined by, 

• conducting percolation tests, or 
• Unified Soil Classification System as described in MMAH  Supplementary Standard SB-6, “Percolation Time and Soil Descriptions”, or  the Soil Texture Classification as described in Chapter 3 of USDA, “Soil  Survey Manual” shall be used to classify the soil.

(3) Where the soil percolation time is determined by a percolation test, there shall be a minimum of 3 locations selected, suitably spaced to accurately evaluate the leaching bed area, with the highest percolation time of the tests being used for the septic design. 

Minimum Clearances Required for Septic Design

Horizontal separation distances to wells, streams, property lines, and other features are regulated and are designed to minimize adverse environmental effects. 

For Septic Treatment Units

• Structure - 1½m
• Well, Lake, Pond, Reservoir, River, Spring, Stream - 15m
• Property Line - 3 m

For Septic Distribution Piping 

• Structure - 5m
• Well with a watertight casing to a depth of at least 6 m - 15m
• Any other well - 30m
• Lake, Pond, Reservoir, River, Spring, Stream - 15m
• Property Line - 3m

Design of an on-site private septic system has two basic parts: a septic tank that receives the untreated sewage and in which solids settle out, and a leaching bed (tile bed) through which the liquid waste portion of the sewage is dispersed into the soil. The main function of the septic tank is to allow solids to settle and to let clear effluent flow to the septic tile bed. Biological reactions within the septic tank will break down some solids into liquids and gases, but the retained solids will eventually accumulate in the septic tank. Only clear liquid waste should be discharged from the septic tank to the septic tile bed. This liquid waste will then undergo further biological breakdown and treatment. To ensure the efficient operation of the entire septic system, it is important that the sludge, scum, and solids that can accumulate in the septic tank do not enter the leaching bed (tile bed). The septic tank should be inspected by a licensed professional at least once every two years and the septic tank pumped out when necessary. The design of an onsite septic system for new construction is always a challenge because of the very limited area available for the septic system due to the required minimum setbacks from the drinking water well, property lines, and the proposed structures. There are a number of different septic designs, configurations, and combinations associated with the choice of the septic tank, septic field, and overall septic system design. 

Our licensed Professional engineers make sure that the septic system is properly designed to handle. Advanced septic treatment systems are very effective in treating septic sewage. With cleaner effluent leaving these advanced septic treatment systems, the size of the soil component (leaching bed) that is needed to complete the septic treatment is smaller than for those using septic tanks only. Advanced septic treatment systems could use one of two small leaching bed systems that are currently approved or authorized in Ontario: shallow buried trench and area bed. Advanced septic treatment systems can be used with a variety of above-ground and in-ground distribution options and offer several unique final distribution options. Advanced control panels, auto-dialer alarm systems, and remote monitoring services make the operation of the septic system simple and efficient. 

Design of advanced septic treatment systems is required when:

• dealing with properties with inadequate conditions for conventional  septic systems
• coping with small lots that can’t accommodate the size of the conventional leaching bed
• building on hard-to-access properties where finding and/or transporting traditional materials for conventional septic systems is costly or difficult
• wanting to provide additional protection to groundwater by additional nitrate reduction which some of the advanced septic treatment units could provide.

Septic tanks do not use oxygen as part of the septic treatment. This is known as an anaerobic treatment. Advanced septic treatment units use oxygen to enhance septic treatment. This is known as an aerobic treatment. Aerobic septic treatment units treat septic sewage by adding air. Aerobic septic treatment units inject and circulate air so that oxygen-dependent bacteria can thrive. The bacteria break down organic matter, reduce pathogens and transform nutrients (e.g., ammonia to nitrate). Aerobic septic treatment units often have a pre-treatment tank where the scum and solids are separated and stored before the effluent is passed to an aeration chamber. At the aeration chamber, the air is added to the effluent, which allows the bacteria to feed on the contaminants thereby producing cleaner effluent. Generally, Aerobic septic treatment units are classified based on the status of bacteria in the wastewater within the treatment unit. Bacteria are either suspended in the liquid or attached to some media. Aerobic septic treatment units require air compressors and in most cases pumps and use an area bed or shallow buried trench for final distribution and treatment. 

In suspended growth septic treatment units, wastewater flows from the pre-treatment tank into the aeration chamber where an air compressor and air diffuser supply oxygen and mix the liquid waste. The air keeps the bacteria “suspended” or floating in the liquid waste. It does not attach to any surface. The oxygen supports the growth of the bacteria and other microorganisms that break down the wastewater and solids. The effluent then flows into a shallow buried septic trench or area bed. Suspended Growth Treatment Units presently used in Ontario include Whitewater, Aquarobic, Aqua Safe and Aqua Air, Biocycle, Clearstream, Norweco, and WSB.
 

The revolutionary Norweco Hydro-Kinetic septic system employs innovative Hydro-Kinetic filtration technology to produce the cleanest, most consistent effluent quality available. Developed to serve homes and small businesses outside of city sewers, the Norweco Hydro-Kinetic septic system uses extended aeration and attached growth processes to treat wastewater and features innovative nitrification-denitrification technology. The Hydro-Kinetic septic system is designed to meet or exceed stringent local regulations for septic design in areas where excessive nitrogen is a concern. In lakefront areas, nitrogen is a threat to aquatic life, wildlife, and recreational use. Nitrogen is reduced to less than 10 mg/L by the Norweco Hydro-Kinetic septic system, which is lower than the USEPA’s standard for drinking water. This demonstrates the Norweco Hydro-Kinetic septic system’s superb treatment performance. 

Norweco Hydro-Kinetic septic system is compact, performant, and affordable to operate and maintain septic treatment solution providing a long-life expectancy and peace of mind. During its successful completion of both NSF/ANSI Standard 40 and 245 tests, the Norweco Hydro-Kinetic Flow Equalized Up Flow (FEU) system, became the only NSF/ANSI Standard 40 and 245 certified residential septic treatment system to pass two consecutive back-to-back tests without performing routine maintenance for a full 12 months and achieved unmatched effluent results of 2 mg/L CBOD (Carbonaceous Biochemical Oxygen Demand), 2 mg/L TSS (Total Suspended Solids) and 7.9 mg/L TN (Total Nitrogen).

Norweco Hydro Kinetic offers 

• Advanced Secondary (class III and B-IV) for discharging toward a subsurface infiltration bed or a stream (subject to local regulation compliance), 
• Tertiary – Disinfection (class V or D-II) for discharging towards a small stream or ditch (subject to local regulation compliance), 
• Tertiary – Phosphorus Removal (class IV or P-I) for discharging towards a lake and 
• Tertiary – Nitrogen Removal (Class N-I) for discharging into nitrogen-sensitive environments. 

In attached growth septic treatment units, wastewater from the pre-treatment septic tank flows into an aeration tank that contains pieces of plastic or other synthetic material. Attached growth septic treatment units rely on oxygen-dependent bacteria to break down wastewater and solids similar to suspended growth units. The difference is that attached growth septic treatment units let the bacteria attach, grow, and thrive on synthetic material (e.g., plastic shavings, balls, etc.). An air diffuser provides continuous aeration around the synthetic material to enhance bacterial activity and septic treatment. Some attached growth septic treatment units require an air compressor. The effluent then flows to a shallow buried trench or area bed. The attached growth septic treatment units presently used in Ontario include Bionest, Bio-Microbics — FAST, Nayadic, and Rotordisk. 

Filtration septic treatment units utilize trickling filter technology. Wastewater flows to a pre-treatment tank. The wastewater then flows from the pre-treatment tank into the septic filtration unit which is filled with materials such as peat moss, sand, or a synthetic medium. As the wastewater trickles or percolates down through the septic filtration unit, a bacterial slime grows and thrives. Typically, trapped air fills the voids in the medium and encourages aerobic conditions where bacteria break down the septic waste as it slowly moves through the filter medium. The effluent then flows to a shallow buried trench or an area bed for final distribution and septic treatment in the soil. 

Septic filter beds can be made verifiable by installing underdrains, which would keep the sand free-draining and aerobic. High-quality effluent from septic filter beds, peat, or foam filters can then be placed in a “shallow area bed” for low-risk disposal. The shallow area septic bed technology, used in Ontario since 1994, affords a two-stage filtration septic treatment train. The “roughing filter” of sand, peat, or foam removes ~95% of the organics and >99% of E. coli. The second “polishing filter” is the fine sand layer in the shallow area septic bed that removes the remaining E. coli for a total of 99.9993% removal before entering the natural environment. The soil and the groundwater are both protected, and health risks are minimized. 

The double safeguard of septic filtration treatment followed by filtration disposal is similar to the preferred “multiple-barrier” approach to drinking water safety. The multi-barrier approach or defense in depth has been an approach that has long been used by the drinking water industry to provide safe and secure supplies of drinking water. The single bio-mat barrier in soil-based septic systems does not provide the safety of the multiple-barrier approach. 

Synthetic Media Septic Filter Treatment Units presently used in Ontario include Waterloo Biofilter and Orenco AdvanTex. The Waterloo Biofilter is an aerobic trickling filter that uses an absorbent synthetic filter material developed by researchers at the University of Waterloo and first installed in Ontario in 1991. Septic tank effluent is applied intermittently to the top of the filter media. The synthetic media supports microbiological growth, and these microorganisms are responsible for the aerobic breakdown of the wastewater. The core of the Waterloo Biofilter septic system is a synthetic, absorbent filter medium that is configured as a free draining, attached growth, biological trickling filter to treat sewage and process wastewater. 

This patented, engineered Waterloo Biofilter medium is consistent in its physical properties and has been optimized to:

• Be stable and consistent over very long periods of time without the  need for cleaning or replacement
• Maximize the surface area to volume ratio thereby reducing the septic system footprint
• Accept very high, long-term loading rates without plugging or compromising septic treatment – typically up to 10 times greater than sand filters or soils
• Simultaneously provide aerobic, anaerobic, and anoxic environments for biological treatment – without air compressors and their high energy use and aerobic sludge production
• Absorb and retain wastewater thereby increasing retention time and providing higher levels of septic treatment
• Maintain biological populations even during periods of no use – enabling consistent septic treatment levels in seasonal applications like cottages, golf courses, and campgrounds
• Eliminate short-circuiting of untreated sewage to the environment during events such as surge flows or power failures

The absorbent Waterloo Biofilter filter medium creates an ideal environment for microbial attachment. Beneficial bacteria colonize the interior surfaces of the absorbent Waterloo Biofilter filter medium where they are protected from predators, desiccation, and freezing. These microbes degrade and oxidize organic pollutants, coliform bacteria, ammonium, and other contaminants as the wastewater is retained in the absorbent Waterloo Biofilter filter medium by capillarity. Air passively circulates throughout the absorbent Waterloo Biofilter filter medium providing an aerobic septic treatment environment without the need for forced aeration. This attached growth process (also referred to as a fixed film process, intermittent filter, packed bed media filter, or percolating filter) outperforms activated sludge or suspended growth (suspended sludge) processes with lower energy requirements, fewer moving parts, simpler operation, less maintenance, and a better ability to handle shock loads of chemical addition or hydraulic overloads. 

Waterloo Biofilter is proven in frigid -50°C temperatures, treating cold sewage with influent temperatures as low as 3°C. Compared to other media-based trickling filters, the Waterloo Biofilter does not slough off microbes in the form of aerobic sludge, maintains high septic treatment levels even in very cold climates, has longer retention times, and can accept much higher organic and hydraulic loads without plugging.  Waterloo Biofilters consistently provide tertiary, sand filter quality effluent (< 10 mg/L cBOD & TSS) that is clear and odourless. Highly treated effluent is easily and safely dispersed back into the soil via small, shallow disposal beds or trenches, or can be reused onsite for purposes such as irrigation, truck washing, or toilet flushing. 

Peat Filter Septic Treatment Units presently used in Ontario include Premier Tech — Ecoflo and Puraflo. The Ecoflo Biofilter is a trickling filter that uses peat to treat wastewater. The Ecoflo Biofilter consists of an open-bottomed fibreglass shell full of harvested peat. Effluent from a septic tank is delivered by pump or by gravity (depending on relative elevations) to the top of the peat media. The wastewater percolates downward through the peat and then through the infiltration zone, which consists of 200 mm of clear stone & 300 mm of clean sand. After moving through this infiltrative zone, wastewater infiltrates into the native soils. The peat acts both as a place for aerobic bacteria to anchor and treat wastewater as it passes through the filter and as a physical filter. Some limited chemical reactions are also achieved. Aeration of the unit is passive, i.e. there are no blowers or fans to enhance air movement through the peat. The peat must be replaced approximately every 8 years. 

Sand Filter Treatment Units presently used in Ontario include Orenco. 

The minimum design capacity of a residential septic system is 1,600 L/ day. The septic tank is designed to store the wastewater for two days or more before discharging it to the disposal field or to further treatment. If you have a larger home, or if your home has fixtures that use additional water (such as hot tubs), or if you have a multi-residential building, you will need a septic system that is designed to receive more wastewater, or problems can result.

Effluent Filter for Septic System

Septic tank effluent filters are designed to intercept solids that might otherwise escape from the septic tank and clog the septic bed. An effluent filter installed at the outlet of the septic tank dramatically improves the quality of effluent being discharged to the leaching bed, effectively extending its life. The addition of an effluent filter to all systems is strongly recommended. Sewage enters the first chamber of the septic tank through an inlet baffle or tee. Most of the larger particles settle out and the effluent enters the second chamber. The second chamber (much smaller than the first) further enhances the settling process. If flows are heavy at times, solids can pass through both compartments and enter the leaching bed. The effluent filter minimizes this. Effluent filters in accordance with NSF/ANSI 46, “Evaluation of Components and Devices Used in Septic Treatment Systems” must now be sized to filter out particles of 1.6 mm [1/16”] and have a minimum area of 550 cm²[85 in²], in addition to being installed in accordance with the manufacturer's requirements. 

Effluent filters:

• Assist in the settling of both large and small particles,
• Help slow down the flow to further enhance particle settling before damage is done to the leaching bed.
• Improves effluent quality.
• Extends leaching bed life.
• Can be used in any septic tank.
• May be installed in a new septic system, or retrofitted into an existing septic tank.
• Corrosion-proof construction.
• Relatively simple installation.
• Simple maintenance.
• Can be equipped with an alarm to warn that the filter needs  cleaning. 

Septic Pumps and Siphons

Where the total length of the distribution pipe required is 150 m or more, the septic system shall have at least one septic pump or a siphon contained in a dosing tank that may be a separate compartment within the septic tank structure, for distribution of the effluent.· Alternating siphons shall not be installed in a septic system.· Where 2 or more septic pumps are employed within a dosing tank, the septic pumps shall be designed such that the septic pump's alternate dosing and dosing shall continue in the event that one septic pump fails.· Where a septic pump or siphon is required, the septic pump or siphon shall be designed to discharge a dose of at least 75% of the internal volume of the distribution pipe within a time period not exceeding fifteen minutes. Septic systems dispose of sewage and rely on the soil to absorb and disperse wastewater. The Septic Systems are designed to keep effluent underground and to filter wastewater before it reaches groundwater, streams, or lakes. “Sewage” can include domestic wastewater from toilets, showers, bathtubs, and kitchen and laundry wastes.

There are various types of Septic Permit designs depending on site conditions. Our licensed professional engineers evaluate the site conditions when selecting or designing a septic system. Septic Systems are designed by our licensed professional engineers to ensure that effluent is properly treated in the septic field and natural soil and that harmful bacteria are removed before it reaches the water table beneath the septic field. Drawing on our experience our licensed engineers can supply information on the procedure for selecting/designing an on-site septic system.

Septic Area Bed

A septic area bed is an infiltrative zone similar to that of a septic filter bed. Septic area beds have very small footprints and are only allowed in conjunction with alternative septic treatment units providing tertiary-level septic treatment. Septic area bed generally consists of a clean stone layer 250 mm thick underlain by a sand layer 200 to 300 mm thick. The sand layer may vary in depth and size depending on the septic treatment unit being used. 

Some advanced septic treatment systems have open bottoms that sit right on top of the stone layer while others have a septic distribution network of PVC laterals placed in the stone layer for effluent distribution. Typically, effluent from the advanced septic treatment system will flow by gravity to an area bed. However, some septic systems have a pump as an integral part of the septic system, and sometimes a pump is added to overcome an elevation difference between the advanced septic treatment system and the area bed. 

The header and distribution pipes within area beds must be designed and built in such a way that they can be detected by one of the following:· Magnetic means.· 14-gauge TW solid copper light-coloured plastic coated tracer wire.· Any other type of subsurface detection.· Landscape design should not interfere with the natural functioning of a septic system. A balanced combination of oxygen and organisms will maintain the healthy soils necessary for the septic system.

Shallow Buried Trench

A shallow buried trench is an alternative to a conventional leaching bed. Shallow buried trenches may only be used when the wastewater has been treated to tertiary standards. A shallow buried trench consists of small-diameter PVC laterals running through open-bottom plastic chambers. The laterals are perforated at regular intervals on the top of the pipe. Effluent from the advanced septic treatment system is pumped under pressure through distribution pipes at regular intervals (time-dosed). 

When the dosing pump is activated, wastewater is forced along the entire length of the lateral and sprayed upwards where it hits the chamber and trickles down into the soil. By sizing the pump correctly, the entire footprint of the septic system is dosed at the same time, ensuring much more efficient septic distribution and use of the soil absorption system. This pressurized distribution allows for small doses to be evenly distributed along the entire length of the trench and greatly enhances the soil’s ability to receive and treat the effluent. 

Shallow buried trenches are typically installed in the natural soil close to the surface of the ground, allowing plant roots and bacteria in the soil to take up additional nutrients. Shallow buried trenches can be installed as one row or several rows to meet minimum trench length standards as required by the Ontario Building Code. This method is versatile because the septic trench can follow an irregular pattern (e.g., around trees). 

The footprint of a shallow buried trench system is much smaller than a conventional septic system because the soil is not relied upon to complete very much treatment. In addition, shallow buried trenches may be installed in native soils with a T-time up to 125 min/cm. A shallow buried trench system is appropriate for sites with a high water table, shallow depth to bedrock, or tight soils.

Ontario Building Code Requirements for Shallow Buried Trench Construction 

• The septic treatment unit used in conjunction with a leaching bed constructed as a shallow buried trench shall provide an effluent quality that does not exceed 10 mg/L Carbonaceous biochemical oxygen demand (cBOD) & Suspended Solids (TSS) concentrations
• The effluent shall be distributed through a pressurized distribution system having a pressure head of not less than 600 mm when measured to the most distant point from the pump.
• The septic pump chamber shall be sized to provide sufficient  storage volume so that the effluent is evenly dosed on an hourly basis over a 24-hour period.
• A shallow buried trench shall not be constructed unless the soil or leaching bed fill is sufficiently dry to resist compaction and smearing  during excavation.
• Every chamber shall be as wide as the shallow buried trench in which it is contained, and the cross-sectional height of the chamber at its centre point shall not be less than half the width of the trench.
• Every chamber shall contain only one pressurized distribution pipe.

MAINTENANCE OF SEPTIC SYSTEMS· 

• Plant grass or keep existing native vegetation. These are the best covers for your septic drain field.
• Direct all surface drainage away from the septic system.
• Use shallow-rooted plants. Tree and shrub roots can grow into the septic drain lines, clogging and breaking them.
• Avoid water-loving plants and trees.
• Make sure the septic tank lid is secure.

Don’t:

· Plant a vegetable garden on or near the septic drain field.

· Put plastic sheets, bark, gravel, or other fill over the septic drain field.

· Reshape or fill the ground surface over the septic drain field and reserve area. However, just adding topsoil is generally is acceptable if it isn’t more than a 5cm (2”)

· Make ponds on or near the septic system and the reserve area.

Plant native, drought-tolerant plants as ground cover for septic drain fields.

The following shallow-root plants are some of the best for planting for your septic drain field:

Grass:

• Fescue
• Lawn
• Ornamental grasses
• Wildflower meadow mixes

Groundcovers for the sun:

• Bugleweed (Ajuga)
• Carpet heathers (Calluna Vulgaris)
• Cotoneaster (Cotoneaster)
• Ground ivy (Glechoma)
• Kinnikinnick (Arctostaphylos)
• Periwinkle (Vinca)

Groundcovers for shade:

• Bunchberry (Cornus)
• Chameleon (Houttuynia)
• Ferns
• Mosses
• Sweet woodruff (Galium Odoratum)
• Wild ginger (Asarum)
• Wintergreen (Gaultheria)

Soil Compaction 

Soil Compaction can bring serious consequences to septic system performance. Any soil treatment area whether it is below grade with trenches, a bed or drip distribution, or above grade with an at-grade or a mound — needs noncompacted soil. Half of a healthy soil’s makeup is pore space, with the other half composed of organic matter and mineral particles (sand, silt, and clay). Pore space provides room for air and water to circulate around the mineral particles, providing a healthy environment for plant roots and beneficial microorganisms. In compacted soils, the particles are pressed together so tightly that the space for air and water is greatly reduced. 

Compaction is most likely to occur with heavier soils like clay and loam, but when heavy equipment is used, sandy soils can also become compacted. Reduced oxygen transfer to the soil treatment area can decrease the life of the septic system, as it needs oxygen to break down the wastewater. Reduced pore space decreases the pathways for wastewater to move through the soil. Lack of pore space translates into a lack of drainage. Reduced microbial community due to decreased oxygen levels. Lack of vegetative cover that is needed to protect components, use water and prevent erosion. In fact, it can be almost impossible to maintain plants in compacted soil because it interferes with the movement of water, air, nutrients, and roots in the pore spaces between soil particles. This makes root penetration and growth harder, leading to poor, shallow rooting; poor plant growth; and a greater need for irrigation and fertilizer. As a result, soil compaction can result in increased costs for the homeowner for water, fertilizer, and, in the end, plant replacement. Also, we do not want fertilizer or irrigation over a septic system drain field.
 

Causes of compaction

• Vehicle traffic - Compaction can be caused or exacerbated by driving on landscapes with heavy equipment during construction or constant traffic such as using unpaved areas as driveways or for parking or mowing repeatedly when the soil is wet.
• Foot traffic - People, animals, or livestock walking over the area will cause compaction, and this problem can be accelerated if the soil is  wet. Avoid having play areas such as swing sets over the soil treatment  area.
• Using the septic system as a path for motorbikes, bicycles, ATVs,  or snowmobiles. In colder climates, this compaction also increases the likelihood of freezing

When construction is occurring near the septic system put up a temporary fence to prevent traffic over the septic system. Install barriers to prevent traffic. Avoid working the soil when it is too wet (this includes mowing). Educate all those on the property about the concerns and consider signage if it’s in a high-traffic area. 

Use of Chemicals

Septic systems thrive on wastewater, but certain chemicals can cause major indigestion. Flushing even small amounts of paints, solvents, thinners, nail polish removers and other common household compounds (or pouring them down the drain) can poison the organisms that break down organic material. 

Laundry bleaches, toilet bowl cleaners, and caustic drain openers can also slow the septic treatment process, allowing sewage to pass through without proper septic treatment. And often, the chemicals themselves seep into the ground, sometimes contaminating wells or surface waters. 

Confirm household cleaning products are septic-safe, biodegradable, and not antibacterial. Vinegar and baking soda can clean about 70% of a home safely and economically, but there are also many biodegradable products in the market today, such as Nature Clean, Ecos, and Citra-Solv. Most retail stores, grocery stores, drug stores, and health food shops offer natural cleaning products.  Liquid fabric softeners cause the most harm to a septic system and should be avoided. Dryer softener sheets, such as Bounce or a non-chemical dryer sheet, are recommended. Potassium Chloride salts are recommended for water softeners. Potassium Chloride is available through hardware stores including Canadian Tire and selected water softener suppliers. 

Reduce the Use of Phosphate

Reduce the use of phosphate-based detergents, soaps, and cleaners since phosphorus in detergents, soaps, and cleaners doesn’t break down in a septic system. When the phosphorus leaches into nearby bodies of water, it can promote algae growth and can impair water quality and fish habitat. 

Oil, Grease & Fat

Septic systems are not designed to digest oils, grease, and fat. Poured down the sink or toilet, they congeal in pipes sometimes plugging them. Grease can also combine with detergents and flow into the drainage field where it may clog the soil. Fats can form a blob in the top of the tank and interfere with the biological activities taking place. All oily waste should go out with the garbage. 

Refuse & Garbage

Using your septic system to dispose of garbage is another no-no. In-sink garbage disposals (“Garburators”) are unwelcome strains on the septic system. Disposable diapers, tampons, and their holders, condoms, wrappers, and many other kinds of refuse can plug and impair septic systems. If something doesn’t break down naturally, don’t flush it into your septic tank. 

Bath Bombs

Bath bombs are hard-packed mixtures of dry ingredients that effervesce when wet. They are used to add essential oils, scent, bubbles, and color to bathwater. They are a mixture of salts, colorants, oils, and solid items such as flower petals or glitter. When added to a bath, the sodium bicarbonate reacts with citric acid to release carbon dioxide gas (like Alka-Seltzer). As it is breaking down, it releases colorants, fragrances, salts, and oils. 

Solid particles in bath bombs could include natural things like lavender buds and flower petals or synthetic materials such as glitter and confetti. None of these items will dissolve. Along with the other items present in the waste stream, these could plug up plumbing and negatively affect the septic system. It is best to use bath bombs that do not contain solid particles, or you could place a length of pantyhose or a fine mesh strainer over the tub drain to collect any solids. The natural products could contribute to the oxygen demand of the septic system and the synthetic ones could accumulate in the septic tank, clog effluent filters, and potentially harm downstream components. 

There are fats and oil in most bath bombs. Oils are liquid at room temperature and will make their way to the septic tank where they will hopefully float to the top and accumulate in the scum layer. Fats or butter in bath bombs can be a problem as they have a variety of melting points and if they cool too fast while traveling through the drain pipes, they can solidify and create a blockage similar to grease in the kitchen. Typical bathwater is usually around 105°F. Cocoa butter has a melting point of around 97°F, but at the end of the bath, the water may have cooled to close to 98°F. When the drain is opened, the pipes are easily going to bring that temperature below the 97°F solidification point and potentially create a buildup in the interior plumbing. 

Most bath bombs have such a low butter content that they should not create much of an issue in the plumbing, but if bombs are used frequently, they could accumulate in piping and the tanks outside the home. Bath “truffles” have a much higher butter content and should be avoided. These oils and greases can accumulate in the septic tank, clog effluent filters or exert an additional oxygen demand in the overall septic system. The salts used in some bath bombs may not totally dissolve. Partially dissolved bath salts can result in clogs as a few undissolved chunks can become caught in the drain, which will then catch hair and other pieces of debris. In high amounts, these added salts will harm the bacteria in the septic system. In general, bath bombs are not a product recommended for frequent use for those on septic systems. For those connected to septic treatment plants, care should be taken to not clog drains. 

Backwash Water from Water Softener

We do not recommend that you discharge backwash water from water treatment devices like water softeners to the septic system unless the system has been designed by a licensed professional engineer to handle the specified water treatment system.

If you have municipal water service, your water meter will record your water use. You can compare water use with the design flow of the system and detect leaking plumbing fixtures. 

Improperly designed, selected, installed, or maintained septic systems can fail. Problems related to the pipes, rock, or soil can result from a poorly designed septic system (inadequately sized for the soil conditions). Remember that if use is greater than the design flow rate, untreated effluent may surface down the gradient of the drain field. The average septic tank should be inspected every 1 to 2 years by a professional septic tank cleaner. If the cover is removed and the tank is full, this does not mean there is a malfunction. The tank is designed to have an outflow level of approximately 75 mm (3 in.) below the inflow level.

When properly designed, installed, used, and maintained, your septic system will be simple, economical, and effective, and will do its work reliably, safely, and efficiently for many years.

Here are a few examples of how homeowners have caused problems with their septic systems. None is covered by the TARION new home warranty.

“That large, flat piece of land was just sitting there, so we ...... built a driveway (patio, deck, tennis court) over it.”

Just covering the grass over the leaching bed will stop evapotranspiration and keep out the oxygen the system requires. Any weight can crush the pipes and make the leaching bed useless.

... used it for our above-ground pool.”

The weight of an above-ground pool will almost certainly crush the leaching bed.

.... used it for our in-ground pool.”

Don’t laugh. It really happened. They got the whole thing excavated, and then somebody flushed the toilet.

.... flooded it so the kids could have a skating rink.”

Leaching beds are carefully built to accept water -- even if it comes from a hose sprayed in the middle of winter. This family managed to freeze their entire leaching bed solid and ended up with water backing up into the house.

... rototilled it for a vegetable garden.”

Pipes can be as little as 375 mm below the ground surface. They can easily get damaged. Besides, vegetables don’t protect the soil from erosion like grass does.

.... made it look pretty with trees and nice landscaping.”

Perforated pipes don’t stand a chance against roots from trees and shrubs. They get clogged or crushed. Either way, the septic system doesn’t work properly.

That huge mound was really ugly, so we ... ... brought the rest of the ground up to match.”

Often, the reason the septic designer designed a septic system with a raised bed is that the site is clay. If owners fill in around the septic bed with more of that clay soil, they end up making a sort of large, almost impervious bathtub. Sooner or later, it will fill up. If they also put a layer of clay soil over top, it can fail within months. The only material that should be used to level the grade is a good sand.

.... cut it off and built a nice-looking retaining wall.”

This family didn’t understand that the whole mantle area is used for filtering wastewater. When they cut it off, the liquid (which wasn’t completely filtered yet) seeped out through that pretty wall instead.

“Nobody ever told me I couldn’t ...... drain the downspouts, sump pump, etc. down the septic system.”

This is a common problem, which can make the actual water flow through the system many times the estimated design flow. It will drown the septic bed.

.... water the lawn over the leaching bed area.”

There have even been cases where people installed automatic lawn sprinklers over the leaching bed area and refused to turn them off. Again, this will drown the septic bed.

.... start a daycare centre, add an apartment in the basement, etc.”

Anything that increases the house water use - and both of these certainly did - can overload the septic system.

.... fill in those ugly ditches.”

“Swales” are used to direct rainwater and melting snow away from the leaching bed. Filling them in changes all that carefully thought-out drainage pattern.

Our Professional Engineers licensed in Ontario design a variety of advanced, innovative, predictable, permanent, robust, cost-effective, compact, low energy, low maintenance, visually subtle, and efficient onsite septic systems for off-sewer developments in Ontario. 

Our septic system designs meet the requirements of the Ontario Building Code and the Ministry of the Environment, Conservation, and Parks and offer the most affordable, long-lasting site-specific septic system design. Inappropriate septic system design, bad construction practices, or poor maintenance can all lead to septic system failure.A small house with a maximum daily flow rate of about 1,000 liters/day, and if that system is being installed in sandy soil (which has a high absorption rate) then the system could be quite small and be installed at a cost of a few thousand dollars. On the other hand, a big house with a maximum daily sewage flow rate of 9,000 Liters/day and hard clay soil (which can only absorb 4 liters, per square meter, per day) then the cost could be over $50,000 because the tertiary septic system may need to be installed. 

Typical stamped engineering residential class 4 sewage system design complying with provisions of Division 8 Part 8 of O.B.C and if required, a design of a tertiary treatment unit, pump chamber, and a shallow buried trench would cost $1,695+HST and upon the receipt of all the required information, could be completed in 5 to 8 business days.
 

If required, a new soil sampling and particle size distribution analysis by an accredited laboratory to find the Unified Soil Classification as described in MMAH Supplementary Standard SB-6 and the "T" time would cost $495+HST for locations in the Greater Toronto Area. If Hydrometer Testing is required, it would cost an additional fee of $125+HST. 

If the client wishes to have two separate septic systems design of a separate system would cost an additional fee of $795+HST. 

If deemed necessary by the Municipality and/or the Conservation Authority, the applicant may be requested to provide supporting reports, assessments, plans, and analyses including the following:

· Seasonal High Groundwater Elevation and bedrock elevations

· General soil properties and conditions

· Geotechnical Report

· Hydrogeological Assessment 

· Calculation of Nitrogen Concentration and/or Phosphorus Reduction· Nitrate-Nitrogen Dilution Calculation

Depending on the scope of work, the fee for preparing any of the above-mentioned reports/analyses may vary.

The septic contractor may have to contact the Municipal Officials to determine their requirements and if they need inspectors on site for the test pit investigation/assessment and arrange for septic test pit digging equipment based on site accessibility. 

We need the following to prepare a Septic Design:

• AutoCAD (dwg) drawing of a detailed site plan showing the location of wells and/or sewage systems on the subject property as well as neighbouring parcels within 35 m of the subject property.
• CAD drawing of the topographic survey and the grading &  drainage plan Architectural Drawings showing proposed floor plans showing the floor area, bedrooms, and plumbing  fixtures.
• Arborist Report & Landscape Architect Drawings showing existing trees to be preserved and proposed locations for all tree protection zones 
• If applicable, the locations of any regulatory flood lines or      development limit lines 

For Additional Information please contact

• Miaoyi Xue, P.Eng,
• Joo Min Park, MEng, P.Eng.
• Saloni Khoja, B.Arch.
• Edgar Labuac, P.Eng
• Weiming Lin, B.Eng
• Rui Cong Xia, B.ASc(Civil)
• Yuen Yu Ng, B.S.Sc (Arch)
• Hoi Ching So, B.S.Sc (Arch)
• Liu Sun, B.Des (Arch)

LAND & BUILDING EXPERTS

Land Line: 416 332 1743

After Hours / Text Messages: 416 727 8336

Email: landbuildex@gmail.com