June 23, 2021

Septic systems 101

You just bought your first home in the country, and you have a ton of questions about the septic system? Not to worry! In this article, we’ll answer several frequently asked questions about septic tanks.

What is a septic tank?

When a home isn’t connected to a municipal sewage system, a septic tank must be installed. These tanks are buried under ground near your home.

Their main purpose is to send wastewater to a reservoir where bacteria break down the liquid or semi-liquid waste. The liquids are then sent by pipe to a leaching field. Liquefied matter is evacuated using drilled pipes. What remains at the bottom of the reservoir is a sludge that needs to be pumped to prevent the septic tank from becoming clogged.

How often should the septic tank be pumped?

Depending on how much it is used, the septic tank should be pumped every two to four years. If it is your main residence, Quebec law requires you to pump every two years. In the case of a cottage or secondary residence, you can wait a little longer.

Note: several municipalities have specific requirements on septic tanks, so be sure to check your local by-laws.

When should you replace your septic tank?

Septic tanks have an average lifespan of 20 to 25 years.

How do you know if it is time to pump your septic tank?

You can open your septic tank lid and send down a stick to see how much slugde has accumulated. If it is more than halfway full, it's time to call on a professional to pump your tank.

You should also keep an eye open for other signs that your septic tank might be full:

  • water (or residue) flowing more slowly in your drains
  • backflow in showers or sinks
  • drains giving off unpleasant odours
  • the grass over the septic tank is greener or growing faster than usual (an overflowing septic tank means the grass will get more water)
  • the soil is soaked around the pit
  • there are unusually large algae blooms in streams or bodies of water near your land (detergents can promote algae growth)

Caution: If you hear dripping noises when emptying the washer or bathtub, the drain could be clogged.

Remember that regular pumping is the best way to avoid problems with your septic tank.

What should you do to keep your septic tank in good working order and ensure its effectiveness?

In addition to regular pumping, it is smart to:

  • refrain from installing heavy structures or driving vehicles over the septic tank
  • avoid throwing tissues, tampons or other products that are more difficult to break down into toilets
  • restrict your use of chemical cleaners
  • avoid pouring liquids such as grease, oil or paint down your drains

The septic system requires micro-organisms to “digest” the materials deposited in it. As such, it’s best to avoid adding items that may interfere with their effectiveness.

If you have a septic tank, here's a little reminder: be careful about what you put in it, pump it regularly and stay alert for any sign of a problem.

For more information, read this Best practices guide (French only).

See also:

Replace your lead piping

Cleaning the Ducts and Pipes in Your Home

Preventing Water Damage With a Sump Pump

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