Table of Contents Ground Water Table Elevation and Percolation Tests

Ground Water Table Elevation and Percolation Tests

Sewage Disposal may be served with individual on-site systems, a new sewage system or extension of an existing system. A soil assessment ensures that on-site disposal is feasible. The Environmental Health Officer of the applicable local office of the Regional Health Authority applies the requirements of the Local Services Act Sewage Disposal Regulations when determining if a proposed parcel can accommodate on-site sewage disposal.

The "ground water table elevation test" is an important part of these Regulations. If the tile field is in water, aerobic bacteria cannot function, and the efficiency of the septic tank system is reduced. If the water is flowing, it may carry the effluent to a highway ditch or to some other property's source of domestic water.

Section 1 of the Sewage Disposal Regulations Site Investigation Schedule states that subsurface ground conditions in the area of the absorption field should be determined by doing the following:

  • Digging or boring a representative number of holes to a minimum depth as required by Environmental Health Officer
  • Reporting the conditions found
  • Leaving the excavated material for inspection
  • Covering the test holes

In areas without sewage systems, water should soak into the soil at a certain rate. The "percolation (perc) test" indicates how fast this occurs.

You may have to delay completion of these tests depending on the season.

Applicants should submit the test results to the District Transportation Office with the subdivision application. The District Development Technician will then forward the test results with a copy of the plan to the local office of the Regional Health Authority for comments and recommendation. If the test results are not submitted with the application, the review will continue but preliminary approval may not be given before the soil tests are complete.

This guide is a living document; it is subject to change without notice. Please check the Rural Subdivisions Website ( to make sure your version is sufficiently current.