Septic Systems
Proper design and maintenance of your septic system is important in ensuring it functions properly and will not end up costing you and the environment. Improperly treated wastewater may contain bacteria, viruses, phosphorus, and nitrogen.
Source: Watersheds Canada
‼️💥 On April 14, 2026, the Township of Lake of Bays approved a septic system inspection program that will introduce phased, risk-based inspections of private septic systems over time. Full details here:
LEARN MORE
OOWA - Homeowner Resources: https://www.oowa.org/homeowner-resources/
FOCA - Septic Systems: https://foca.on.ca/septic-systems/
OMAFRA Septic Smart!: https://www.ontario.ca/page/septic-systems
A septic system treats and disposes of household wastewater by separating it into layers in the tank: Sludge (bottom layer), scum (top layer) and liquid waste (middle layer). It is the liquid waste that is passed out through the distribution box and into the leaching bed, where it flows through a network of pipes before entering the surrounding soils. Solids accumulate over time and must be pumped regularly; failure to do so can lead to backups, field clogging, and environmental contamination.
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Why Best Practices Matter
- Protects human health and the environment
- Extends system lifespan
- Reduces financial risk from contamination or system failure
- Supports informed land-use decisions
- Encourages shared stewardship among rural landowners
- Test water 3–4 times per year (seasonal tests for cottages). Free E. coli/coliform testing available via Public Health Ontario
- Create an inventory of potential contamination sources (examples include household chemicals and cleaning products, paints, solvents, oils and fuels, fertilizers and pesticides, animal waste, and stormwater or runoff from other properties carrying contaminants toward your septic field)
- Establish a protection zone around wells/intakes (approx. 100 m)
- Visually inspect wells and septic systems annually
- Pump septic tanks every 3–5 years
- Use eco-friendly cleaning products, fertilizers, and chemicals
- Conserve water to protect quality and quantity
- Dispose of hazardous waste safely
- Inspect fuel storage and use double-walled tanks if possible
- Maintain vegetated shoreline buffers to reduce runoff
Systems with daily flow < 10,000 L are regulated under Part 8 of the Ontario Building Code. The Code defines:
- Design and construction standards
- Licensing of installers, designers, and inspectors
- Permitting and inspection responsibilities
- 15 m from drilled wells
- 30 m from dug wells
- 15 m from surface water
- 5 m from leaching beds to structures
- 1.5 m from tanks to structures
- Gravity Feed: Wastewater flows naturally (by gravity) from the house to the septic tank and then to the leach field or tile bed. Simple, relies on slope, no advanced treatment.
- Pump to Tile Bed: Wastewater is pumped from the septic tank to the leach field (tile bed) when gravity alone isn’t enough. Still mostly primary and secondary treatment (settling solids and some bacterial treatment).
- Tertiary System / Advanced Treatment Unit (ATU): This is more advanced than standard septic systems. Provides tertiary treatment, meaning it removes additional pollutants beyond solids and basic bacteria — such as nutrients (nitrogen, phosphorus) and sometimes pathogens. Often required in sensitive areas near lakes, rivers, or drinking water sources. ATUs usually include mechanical or biological components (like aerators, filters, or UV disinfection) to clean the water more thoroughly.