A septic tank is the central component of a residential septic system, but the tank is dependent on a properly functioning drain field. Homeowners who postpone septic-tank pumping for too long sometimes incur damage to the drain field.
The drain field is also referred to as the leach field. The purpose of the leach field is to percolate wastewater back into the soil. In a properly functioning septic system, the only effluent exiting the tank should be a relatively clear liquid.
The leach field contains a network of underground drain pipes. The pipes are perforated and surrounded by gravel. The width of each gravel stone is greater than the size of the holes in the drain pipes. The gravel allows wastewater to flow from the pipes before percolating into the surrounding soil. The whole drain system is topped with a layer of soil, so you may not know the field's exact location until you notice a problem.
Symptoms of slow draining
A pooling of water in the leach-field area may indicate that your drain field is not functioning as designed. The optimal size of a drain field is related to the size of the septic tank and the number of household occupants. Even if the size of the leach field is adequate, the pooling of water can be caused by a variety of factors.
Full drain-system failure
A common cause of leach field failure is clogged drainage. The perforated pipes are typically laid in trenches during their installation before being surrounded by gravel. The trenches are typically about six feet apart, which allows space for additional trenches to be dug for replacement pipes. In many instances, you may not need a full drain field replacement.
Partial drain repair
Trees planted too close to a drain field can cause problems. The root system of a tree can grow vigorously once it finds its way into a leach field. However, the damage caused by a tree to a single drain trench may be repairable. Even if the drain field seems to be working properly, precautions are necessary to protect the underground pipes.
Try to avoid parking or driving on the leach field. If possible, divert water from gutter downspouts away from the direction of the drain field. Even if the native grass growing above a leach field appears to be a bright-green color, the area should not be used for growing much beyond ornamental grass or wildflowers.
Septic tanks are available in various sizes to accommodate different house sizes. The best method of extending the life of a leach field is to have the tank pumped on a timely basis. Contact a septic-system specialist for more advice on drain-field services.