One of the largest parts of any private sewage disposal system is the septic tank drain field and maintaining it should be part of overall home maintenance. By design the field needs to be close to the tank but situated away from the house, as far as physically possible, and needs to provide a free-flowing area for the drains to function properly. Since most depend on gravity to move the effluent through the pipes underground it is imperative they remain free of obstruction and damage.
Many of the pipes in the drain field are fairly close to the surface and driving heavy vehicles over the top can damage the pipes and cause a major problem to its operation. Additionally, planting trees or shrubs over the area can allow roots to grow into the underground pipes causing them to break or at the very least, cause them to become blocked.
Similarly, trees with fast-growing roots can pose a major problem. Certainly, don’t plant new trees over the field, but the more likely scenario is that you have a tree you love and don’t want to cut down. Be sure it’s not one of the trees with aggressive roots, or it might lead to a very expensive problem. It might also be possible to kill the roots without killing the whole tree.
As your tank fills with sludge, the liquid layer, known as “effluent”, rises. There is an outlet inside the tank and when the effluent layer reaches that outlet, it flows out into the drain field. From there it passes through the underground pipes, filled with small holes, allowing the liquid to leach back into the soil. The sand and dirt under the pipes serves as a filtering system to remove many of the particulates that may still remain in the effluent. This makes the water going back into the ground clean.
Tanks that do not have the sludge layer pumped out regularly are likely to allow some of this waste material to escape. When this happens, blocked holes in the drain pipes can pose issues in the field resulting in surface flooding which can also allow untreated waste to accumulate on or near the surface, subsequently flowing into nearby streams and creeks. Any chemical or biological materials in the waste will also flow, creating a potential environmental hazard.
When the field becomes blocked, companies may provide chemical or biological solutions in an effort to open the lines. However, if those efforts fail you may have to have it dug up in order to pinpoint the cause of the blockage and effect repairs. By no means will this be a cheap and easy process, but once the soil and small pipes have become blocked it may be the only available solution.
When using chemicals in an effort to reopen a clog, you will want to check with the local health department first. Some states and even some communities restrict the types of additives that can be used in a system in order to preserve the integrity of the local water supply.
Tank and Field Diagram