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Septic Systems 

The use of private septic systems is an important issue in Muskoka, as there are over 25,000 systems in the waterfront and rural areas of the District. A malfunctioning system can pollute both ground and surface water.

toiletIn Muskoka, private sewage systems are regulated by the Area Municipality. In other parts of the province, the local health unit or conservation authority may be responsible for upholding septic system standards.

The Ontario Environmental Protection Act classifies most private sewage systems in Muskoka as Class 4. This type of system includes a septic tank, distribution box (optional) and a leaching or tile bed. All wastewater flows from the building to the septic tank where it settles and separates into 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.


Is your septic system the right size?

To determine the size of septic tank required on your property, you need to know the floor area of the building, the total number of bedrooms and the total number of plumbing fixture units.

Type of fixture units

  • Bathroom group (toilet, sink, tub or shower)
  • Toilet
  • Sink (per compartment)
  • Bath tub (with or without shower)
  • Shower stall
  • Dishwasher (separate discharge from sink)
  • Garbage grinder (separate discharge from sink)
  • Washing machine or laundry tubs
  • Hot tubs and whirlpools evaluated individually

Calculate the daily design flow rate using the chart below as guidance. Your septic tank must have a minimum working capacity of 2x the daily design flow rate, with a minimum tank size of 3,600 litres (800 gallons). 

Septic Flow Chart


Where should you put your septic system?

The Ministry of the Environment requires that your:

  • Tank is 1.5 m from any building
  • Tile bed is 5 m from any building

Both must be at least 15 m away from any surface water and drilled wells. If this is not possible or if you have a high water table on your property, the septic bed must be raised above ground using imported soils.

The bed should be more than 1.5 m above bedrock and at least 1.2 m above the water table.


Areas to avoid

Soils that contain a lot of silt and clay do not allow water to seep through properly. These areas should be avoided for septic bed locations. Also avoid areas with a lot of vegetation.

Please see the Building Code Act (Section 8.1) for more building code regulations and septic system information.


Maintaining your septic system

There are many things you can do to extend the life and efficiency of your septic system. For more details visit the Septic Smart section of the Ontario Ministry of Agriculture, Food & Rural Affairs website or review the Muskoka Watershed Council's Best Practices Brochure on Septic Systems.

Learn more about septic system maintenance


Signs that your septic system is in trouble

  • Drains or toilets are backed up or running slowly
  • Sogginess in the ground around the septic tank or leaching bed
  • Unusually green or thick grass growing in or around the leaching bed
  • Significant algae growth in or around nearby lakes or waterbodies
  • High levels of nitrates, bacteria or other contaminants in well water

There is a more complete list of signs that your septic system is in trouble in the Guide To Operating and Maintaining Your Septic System.