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Planning Library>Land Use Planning Information>Septic Systems>Locating a Septic System - Construction

Locating a Septic System - Construction

Before any construction is allowed to proceed, precautions should be taken to ensure that the absorption site is protected from the compaction that might occur from construction traffic. Be sure to stake off and fence this area as well as an additional 90 feet downslope.

Under no circumstances should construction traffic be in this area. Nor should it be used for storage of construction materials. Even the backhoe used to construct the trenches can cause compaction if soil conditions are not ideal. Dig from the upslope side!

Before allowing construction to proceed, be sure that the soil is relatively dry. If the soil is too wet, construction will damage soil structure. This could cause the septic system to function improperly.

A good test for determining if the soil is too wet to excavate is to take a small amount and try to form a ribbon of soil in your hand. If the soil holds the ribbon when you open your hand, it is too wet to allow construction to proceed.

If the soil crumbles and will not stay formed when you open your hand, then it is probably safe to allow construction to proceed.

It is best to plan the construction of your septic system to take place from the middle to late summer months. This is when the ground will generally be the driest and the water table at its lowest.

In the fall the water table usually rises due to the fall rains. It may be difficult to find a time during the fall when the soil will be dry enough to work and the water table not so high that it floods the trench construction.

During the winter, the water table may fall some from its fall level, but the soil will still be too wet to work even if it is not frozen.

In the spring the water table is often very high as a result of spring rains and runoff from thawing snow and ice. Do not plan construction for the spring unless an early and dry summer is expected.