What is a septic system?

When you flush the toilet in a town or city, the waste is piped through the municipal wastewater system to a sewage treatment plant. That plant treats and separates the waste into water that’s clean enough to be discharged into a river and into solids called residual waste.

In rural areas where homes are not connected to the municipal wastewater system, household septic systems provide the same service on a much smaller scale. Wastewater leaves the house and empties into an underground septic tank where the treatment process occurs.

Diagram of a two-chambered septic tank showing how the wastewater flows in, the sum and sludge settle out and then the water flows through the outlet.

How does it work?

Most septic tanks have two chambers. The first chamber receives all the household sewage from toilets, showers, sinks, dishwasher, etc. The solids (sludge) sink to the bottom of the tank, and fats, oils and grease (scum) float. The remaining water (known as effluent) then passes into the second chamber.  From the second chamber in the septic tank the effluent is either sent to a septic field, or a wastewater lagoon or lift station.  

Maintaining your septic system

Never enter your septic tank for any reason! Septic tanks can contain toxic gases such as hydrogen sulphide. If your tank needs maintenance, make sure to call a professional.

Did you know that as a homeowner you’re responsible for maintaining your septic system? A typical septic system should be inspected every 12 to 36 months by a septic system service provider. Systems that have electrical float switches, pumps, or mechanical components need to be inspected more often.

Your septic tank should also be pumped out regularly as recommended by your septic system service provider (generally every 18 to 36 months). Four major factors influence the frequency of pumping:

  • the number of people in your household
  • the amount of wastewater generated
  • the amount of solids in the wastewater
  • septic tank size

Identifying problems

The most obvious septic system problems are easy to spot. Check for strong smells,  pooling water, or muddy soil around your septic system or in your basement. Notice whether your toilet or sink backs up when you flush or do laundry. Check with a septic system professional if you see such signs.

Just like changing the oil in your car, preventive septic system maintenance will extend the life of your system.

A permit for a Private Sewage Disposal system is required for the installation or replacement of any of the following: 

  • sewage or privy holding tank
  • septic tank with treatment field, mound or open discharge
  • treatment plant and at-grade treatment field or mound
  • septic tank connected to low-pressure main

Septic system tips:

  • Conserve water and spread out water use to avoid large volumes of water entering your tank in a short period. This will allow time needed to properly separate the sludge and scum from the  wastewater in the first chamber of the septic tank.
  • You can find helpful water conservation tips at strathcona.ca/waterconservation.
  • Don’t dispose of household hazardous wastes, personal hygiene products, paper towels, cigarette butts, condoms, etc., in sinks and toilets.
  • Don’t pour fats, oils, and grease into your septic system. They can cause blockages in your system, and if they enter a lift station can cause service disruptions and environmental damage.
  • Use soaps that are low suds, biodegradable, and low or phosphate free.
  • Have your septic system inspected every 12 to 36 months by a trained professional.
  • Pump out your tank every 18 to 36 months depending on your system.
  • Mark the location of your septic tank and don’t drive or park vehicles on any part of your septic system.
  • Do not plant trees or shrubs near your septic system as roots may clog and damage your tank or pipes.
  • Look for warning signs of your septic tank efficiency such as unfamiliar smells, damp areas around your tank, or slow drains. If any are noticed call a trained professional.
  • Follow the system manufacturer’s directions when using septic tank cleaners and additives.


Water and wastewater services and 24-hour emergency
Phone: 780-467-7785
Fax: 780-464-0557
Email: scutilities@strathcona.ca

Last updated: Thursday, January 27, 2022
Page ID: 51077