Grass Over Septic Tanks

Stressed Turf Over Septic Tanks

By Jan Hygnstrom, Extension Project Manager

With summer heat and drought, some rural residents may find small areas of stressed turf in their yards. Upon further investigation, they realize this is the turf above their septic tank.

While areas over the drainfield may remain lush and green due to movement of wastewater through the soil, providing moisture and nutrients for grass, conditions are quite the opposite above the septic tank. Usually tanks are shallow, with only a foot of soil above them. This shallow soil heats up rapidly from hot summer temperatures so that turf is often the first to show signs of stress.

While it is not recommended to water lawn over the drainfield, some irrigation may be needed above the septic tank if you typically water your yard. The tank is required to be watertight, so irrigation water should not be able to enter it.