Septic Tanks

Is my septic system compliant? Self-inspection guide

By Mélanie Renaud

Have you ever wondered if your septic system may be polluting the environment? Are you worried about the proliferation of aquatic plants in front of your cottage? A specific area of your lot is often saturated with water but you don't know why?

After inspecting hundreds of septic installations, I have noticed that the vast majority of property owners did not know that their installations were non-compliant.  The inspection of a septic system is fairly easily performed, but one needs to be properly informed. This short article will address the various components of a wastewater treatment system and describe the steps to follow to carry out an inspection.


Greywater: household wastewater (from the kitchen, laundry room and bathroom) with the exception of toilet wastewater.  Wastewater contains greywater, but also includes toilet wastewater. It is important to distinguish greywater from toilet wastewater as this will have a significant impact on the inspection of our septic installations.

Septic tank

The septic is also known as the primary treatment system. It is a large sealed tank made of plastic (polyethylene) or concrete. Its dimensions must meet the requirements set by provincial regulation Q-2, r.8, based on to the number of rooms in a residence. Depending on the type of soil and the configuration of your lot, you may have a two-compartment septic tank (most common) or a holding tank type of installation.   The septic tank should be drained regularly (approximately every 2 years, depending on use) while the holding tank must be emptied when full.  It is also possible to have ‘’2 septic tanks’’. If this is your case, you actually have a septic tank as well as an advanced secondary treatment system, also known as Bionest, Ecobox or Ecoflo.

Drainage field

Without going into too much detail, the drainage field is designed so that liquid waste flows out of the septic tank (or secondary treatment system) for final treatment by way of infiltration into the soil. The drainage field may consist of absorbent beds, trenches or wells in the soil or of any other technology that is approved by the Bureau de normalisation du Québec (BNQ

Inspecting your system

Firstly, it should be noted that it is extremely dangerous and potentially deadly to penetrate inside of a septic tank, pumping station or any other enclosed space that is part of a wastewater treatment system. The decomposition of organic matter by bacteria causes a high production of carbon dioxide (CO2), methane (CH4) and hydrogen sulphide (H2S). The action of these gases on an individual can cause death in minutes.

To begin your inspection, you will only need a camera, a little attention to detail and a friend. If you can access your property’s plumbing, this is a good place to start. Follow each of the pipes from sinks, clothes washer, dishwasher, and toilets to ensure that they all drain into the inlet pipe leading to the septic tank rather than into the house’s drainage system. If you don’t have access to those pipes, it is not a big deal. Open the septic tank’s first hatch and ask your friend to observe the inlet pipe (pipe that originates from the house and enters the septic tank). Meanwhile, go inside, turn on a faucet and let water run until your friend can see water flowing into the septic tank.  Repeat the process by activating all water-using appliances and fixtures throughout your home (toilets, clothes washer, dishwasher, etc.) to makes sure that the water being evacuated reaches the septic tank.  This may seem surprising, but at one time, the greywater from washing machines, among other things, was often drained into the house’s drainage system and thus discharged into the environment. In my experience it was common to find that several properties polluted this way. If this is your situation, it is very easy to fix this by asking a plumber to connect the appliance hoses and piping to the septic tank’s inlet pipe.

Secondly, in order to verify if your tank is sealed and in good condition, you will open both compartments. The water level must be at the bottom of the outlet pipe and lower than the inlet pipe. The tank must be leveled. Baffle plates are devices which guide the input and output flow of water to and from the septic tank and they must be in good condition.  The same applies to the wall separating the both tank compartments (does not apply to a holding tank). With your camera, you can simply reach inside the opening of the tank and take hit or miss pictures. Be careful not to trip and ask your friend to hold on to you tightly. Subsequently, you can look at your photographs of the interior of the septic tank to see if it is watertight and ensure there are no cracks or tree roots that have penetrated the walls.

Finally, to assess the condition of your drainage field, turn on a faucet at full capacity,  let water run for 10 minutes (do not attempt this if you suspect breakage in you water pump) and walk onto your lot, up to the location of your drainage field. Look for water surfacing through the grass. Repeat this process twice, at 15 minute intervals.

This inspection does not replace an inspection carried out by a professional or municipal inspector, but it can give you very good indicators of the condition of your septic installation and even allow you to eliminate situations that are sources of environmental pollution. 

Please note that this guide does not in any way replace the information available in the Regulation respecting waste water disposal systems for isolated dwellings (Q-2, r.8). Municipal authorities are responsible for enforcing this regulation through compliance inspections. Your collaboration with municipal inspectors is essential for the protection of the environment as well as for public health. So be accommodating as their work contributes to the well-being of us all.  For more information, I invite you to consult the « Technical guide on wastewater treatment for isolated dwellings» at : and to communicate with your municipality’s inspector.

Vidange de fosse septique

Septic installation of an isolated dwelling:  excerpt from