What Causes a Leach Field to Fail?

Poor Construction

• Leach fields built in poorly draining soil fail because contaminants in the wastewater are not naturally removed. According to Purdue University's Cooperative Extension, site location, construction, design and soil quality are crucial to the long-term success of your septic system. You can find an experienced septic-system contractor by contacting your local health department.

Failure to Pump Septic Tank

• Septic tanks require periodic maintenance. The Anne Arundel County, Md., Health Department recommends having a licensed liquid-waste hauler or disposal contractor pump your septic tank to remove settled sludge at least once every three years, depending on your usage rate and family size. Sludge build-up in the tank can cause sewage to leak into the leach field, contaminating surface soils, ponds, streams and wetlands.

Chemical Additives

• A septic system is a natural, living environment. Chemical additives advertised to extend the life of your septic system can actually damage it and cause your leach field to fail. Additives can suspend sewage matter, forcing it into the leach field. Household fats, cleaning chemicals, greases and oils pumped into the septic system also interfere with the natural processing of wastewater.

Invasive Plantings

• Deep-rooted shrubs and trees planted on top of or near the leach field can cause significant damage to the septic system by tangling septic pipes. Generally, shallow-rooted shrubs, most flowers and native grasses do not harm leach fields.

Construction and Vehicles

• You should not construct patios or walkways over your leach field, even if the leach field is in your backyard. Construction prevents naturally occurring evaporation and can damage pipes and other components of your septic system. Similarly, driving tractors and cars or trucks over the leach field can harm it.