In Québec, a new septic system always follows the same process: a site characterization study carried out and signed by a professional, a permit issued by the municipality, work done by a contractor according to the plans, an inspection, and then backfill. The permit must be obtained before any work begins. At Wilfrid David in Chénéville, we carry out the excavation and installation of septic tanks and leach fields across La Petite-Nation. Here are the steps of a project, along with what the regulation requires at each stage.
First step: contact the municipality
Your municipality enforces the regulation respecting waste water disposal systems for isolated dwellings (Q-2, r. 22). It issues the permit and may have additional requirements of its own. We recommend contacting the municipal inspector or environment officer before committing to any expense. They can tell you which documents to provide and in what order.
If you are considering buying a vacant lot, take this step before you sign. The environment ministry points this out in its brochure for property owners: not every lot can accommodate a compliant septic system, and the soil study may conclude that an installation is not possible. It is better to know before buying.
The site characterization study
What is commonly called a soil test or perc test is, in the regulation's terms, a characterization study of the site and the natural ground. Under section 4.1, it must cover the site's topography, the slope of the land, the soil's permeability, the depth of the bedrock, the water table and any low-permeability soil layers, as well as anything else that could affect where the system is located. Test pits are dug on site, often with an excavator or an auger.
For an isolated dwelling, section 4.3 requires the study to be signed by a professional under Québec's Professional Code whose order governs that activity. The ministry gives engineers, technologists and geologists as examples. One exception applies: if the chosen system is an above-ground sand filter, or a polishing field in impermeable soil, the study must be signed by a member of the Ordre des ingénieurs or the Ordre des géologues, and the location plan by an engineer.
The professional also prepares a location plan to scale. Distances are measured precisely, since the regulation sets minimum setbacks (section 7.2). The non-watertight part of the system, the field, must among other things be at least 15 m from a lake or watercourse and 2 m from the property line. From a well, the distance ranges from 15 m to 30 m depending on the type of well. On a small waterfront lot, these setbacks determine where the system can go.
We recommend being on site when the test pits are dug. The professional will ask about your plans, such as adding a garage or a bedroom, because the number of bedrooms is used to size the tank and the field.
The permit application
Once the study and plan are complete, the application is filed with the municipality. Section 4.1 sets out the basic content: your contact information, the lot's cadastral designation, the number of bedrooms, the characterization study and the location plan. Section 4 is clear that the permit must be obtained before work begins. Your municipality may require other documents or fees, so check with them.
The installation work
The ministry notes that only contractors holding RBQ licence subclass 2.4, for autonomous wastewater treatment systems, can legally carry out this work. The licence registry is available online on the Régie du bâtiment du Québec website. Wilfrid David's licence (RBQ 1842-2873-08) includes subclass 2.4.
On site, the work follows the professional's plans: excavation, setting the tank, preparing the bed, laying the pipes and building the field. If the soil encountered differs from what the study describes, such as shallower bedrock or unexpected water, the contractor must notify the professional and the municipality without delay.
On your side, clear the work area of anything that could get in the way or be damaged. If the system includes electrical components, the hookup is done by an electrician.
Inspection, compliance attestation and backfill
An important point should be noted here. Regulation Q-2, r. 22 does not itself require a certificate of compliance after the work for a house. Some municipalities, however, require an attestation of compliance, and the ministry strongly recommends requesting one even when it is not mandatory, to protect the owner. To issue it, the professional must inspect the work. Agree on the timing of that visit in advance, ideally before the components are covered. Your municipality will tell you whether it requires one.
Backfill and grading follow. Before the system is put into service, the ministry recommends filling the septic tank with clean water to at least two-thirds of its height. If your system includes a treatment unit certified to the NQ 3680-910 standard, you must hold a maintenance contract at all times and file a copy with the municipality (section 3.3). Keep every document: study, permit, plans and attestation. A buyer or the municipality may ask for them.
When to call a professional
Contact us as soon as you are planning to build or replace a septic system, even before the site study: we can explain the steps, then carry out the excavation and installation according to the professional's plans. Details are on our septic systems and excavation pages. Call us at 819-428-3161. If your concern is an existing system, start with our article on the signs of a failing leach field, then the one on how often to pump a septic tank for proper maintenance.
Filed under Septic systems · Excavation
