Soil study and septic system design

The installation of a domestic sewage treatment system is a key component of land development. However, even before its implementation, several parameters must be studied to determine the feasibility of the project and the type of system needed.

A septic system design is therefore required and designed according to the specific characteristics of the site and its natural terrain. It must also ensure that it complies with the standards established by the Environmental Quality Act(Q-2, R. 22) in order to offer you the best possible solution.

In the same way, in a case of compliance, a revision of the system is then made according to the characteristics of the site, the land and the most updated regulations.


Some prerequisites are necessary before a sanitary installation design.

Important documents are required before undertaking a complete septic system design. To consult the list of documents necessary for an efficient realization, click here.

Please note that for a pre-purchase soil test, no documentation is required.

A complete septic system design mandate therefore includes 4 essential steps:

1. Site characterization study (soil tests)

Soil testing can be done before or after the purchase of the land in preparation for development. During a visit, professionals (technologists or engineers) take samples that will be analyzed to determine the quantity and size of minerals contained in the soil. This measure plays a determining role in the permeability of the soil. The tests also allow us to determine the different types of septic systems possible in relation to the natural layout of the land.

At the same time, the experts note, among other things, the characteristics related to the type of soil, the topography of the site and the natural slope of the land.
2. The taking of readings

Taking measurements is a critical step in the process, as these measurements will be used as a reference for the design of the plan and the spatial layout of the system. Specific distances must be respected according to established standards.
3. The septic system plan

The design is submitted in plan form and is accompanied by a report containing the results of the site characterization. The plan includes all the elements for the installation of the treatment system, its components and the distances to be respected.
4. Production of a certificate of compliance and an “as-built” plan

Not all municipalities require a Certificate of Compliance. However, it is strongly recommended to produce one when moving to a new location to facilitate future real estate transactions such as the eventual resale of the land.

It can also happen, during the installation, that unforeseen events occur and require slight modifications to the original plans. In such a case, the municipality may ask you for an “as-built” plan including the updated plan after the work.