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Protecting your drainfield

3 Plastic drainfield pipes exposed on the grountYour drainfield is critical to the health of your septic system and needs to be protected. The pipes and other components in your system may not be buried very deep below ground and could be easily crushed. The soils in your drainfield contain oxygen-loving bacteria that break down and filter the effluent. If the area is compacted by driving or parking on it, the bacteria won’t be as effective and will reduce the ability of the water to percolate through the soil. You will also want to avoid doing anything that overwhelms the system with too much water.

To protect the lifespan of your drainfield, avoid these activities.

Building structures on the drainfield, including tool or garden sheds, decks, sport courts, patios, swing sets, sand boxes, or compost bins.

Parking or driving vehicles or construction equipment on the drainfield.

Planting trees and large shrubs near the drainfield. They should be planted at least 30 feet away to prevent roots from getting into and breaking or clogging the drainfield pipes.

Using a rototiller which could damage the system parts that are close to the surface.

Over irrigating in the drainfield area, as this could saturate the soil and decrease the ability of the system to function properly.

Directing water from your downspouts and surface water runoff onto your drainfield.

Burning piles of leaves or branches over the drainfield, as the heat could damage the plastic pipes below, if they are buried shallowly.

Using plastic sheeting over these areas in an attempt to block weed growth.

Using too much topsoil or compost. Limit to no more than two to three inches over the drainfield.

A good rule of thumb for landscaping over drain fields is to use shallow rooted plants.

2 drainfield pipes exposed with house in background
Drainfield being installed

Many grasses have shallow root systems and are the simplest and most frequently recommended plantings over the drainfield. Choose a traditional lawn or perhaps an un-mowed meadow. You may include permeable pathways, garden ornaments, bird baths, sundials, tables and benches.

In sunnier locations, perennial gardens can be created with mixes of ornamental grasses of different heights and can be inter-planted with ground covers, small bulbs, and sun loving perennials as well as smaller, shallow rooted shrubs. Avoid larger ornamental grasses and bamboo, which are known to harm septic fields.

TIP: Avoid planting vegetables over your drainfield. Vegetables often need daily watering and excess water in the soil reduces the drainfield’s ability to treat wastewater. Roots of some vegetables may grow deep enough to damage or clog drain pipes. If the drainfield is not working properly, the effluent in the drain field could contaminate the vegetables.