Caring for your drainfield

The drainfield is where your wastewater actually gets treated, by soil and the microbes living in it. The tank protects the drainfield by keeping solids back. Nothing protects the drainfield from what happens on the surface except you. Here's how to look after it.

Keep the weight off

EPA's first rule for the drainfield is to never park or drive on it. The weight of cars, trucks, and equipment compacts the soil and can crush pipes. Compacted soil can't absorb effluent. Don't build on it either: no sheds, patios, pools, or play sets. Keep livestock off it too.

Plant the right things

Grass is the best cover. It holds the soil, uses some of the water, and lets air in. EPA advises planting trees an appropriate distance from the drainfield so roots don't grow into the pipes. A septic professional or the county can tell you how far that is for the species you have in mind. Avoid vegetable gardens directly over the drainfield.

Keep extra water away

The drainfield can only absorb so much. EPA recommends keeping roof drains, sump pumps, and other rainwater drainage away from it, because extra water slows or stops the wastewater treatment process. Check where your downspouts discharge, and grade the ground so surface water runs away from the drainfield.

Inside the house, the same idea applies. Spread laundry across the week, fix leaks, and don't drain a hot tub or pool into the system. See saving water on septic.

Keep solids out

Solids escaping from the tank are the other big threat. Penn State Extension explains that as a tank fills, solids get carried out to the absorption area. There they help form a biomat that clogs the soil. An effluent filter on the tank outlet helps, but the real protection is pumping before the tank is too full. Start with our pumping calculator and confirm with inspections.

Let it rest

Penn State research found that drainfields benefit from periodic resting. Penn State suggests one practical trick: schedule the pump-out for the day before the family leaves on vacation, so the soil can dry out and any biomat can break down while the house is empty. Some systems have two drainfields and a diversion valve so one can rest while the other works. If yours does, ask your provider how often to switch.

Signs the drainfield is struggling

Soggy ground, sewage smells, bright green stripes of grass, or slow drains throughout the house can all mean the drainfield is overloaded or clogged. See signs your septic system is failing for what to do.

And protect your well

EPA explains that effluent from the drainfield eventually reaches groundwater. If a drinking water well is in the path of that groundwater flow, especially a shallow well in sandy soil, it's at greater risk. A healthy drainfield that treats effluent properly is part of protecting your water. See protecting your well from your septic system.