A clogged septic drain field isn't the type of problem that goes away on its own; ignoring the problem may lead to needing a complete replacement, which can be costly. Check the drain field for symptoms such as odors, overly green grass or a perpetually wet lawn to ensure the problem really is the drain field. Unclog the drain field by allowing it to dry thoroughly, cutting water use and replacing damaged pipes leading to the drainage area.

Signs of a Clogged Drain Field

  • Slow drains may indicate that the drain field is clogged, especially if this happens along with other symptoms.
  • If it takes several flushes to move an average amount of waste from the toilet, the drain field may be clogged. As with the slow-drain issue, this problem may concern the drain field if several other problematic signs are present.
  • Grass that is greener over the drain field area than in other areas of the yard may also indicate a clogged drain field.
  • A yard that feels wet or spongy when it should be dry is a sign of a drain field clog or partial clog. The wetness may occur over the drain field or slightly downhill from it. This is often one of the first signs of drain field clogs.

How it Happens

When a home has a septic system, everything that goes down the drain or toilet travels through the septic system. Over time, grease, soap and solids may build up in or near the drain field, restricting the flow of water. Continuous use leads to even more buildup, and eventually the water traveling through the drain field can no longer flow naturally, resulting in pooled water and unhealthy septic conditions. If the clog is bad enough, drains may even back up within the home. Clogging may also happen due to excessive rainfall, too much water running through the pipes, or even cracked or partially blocked pipes leading to the drain field.


Prevent drain field problems by cutting back on water use and not running a lot of water through the septic system in a short time. Do not pour grease or oils down the drain and do not flush paper towels or foreign matter down the toilet. Use only toilet paper designated as safe for a septic system. Avoid driving over pipes that lead to the drain field whenever possible, as the weight of a vehicle may crush them.

Repairing the Drain Field

In some cases, allowing the drain field to dry out removes the clogging problem, although this is a little more involved that in sounds. Reduce water usage in the home as much as possible by replacing shower heads and appliances that use a lot of water with more efficient water-saving versions. Stagger showers, dish washing and general water use to avoid overloading the septic system. Pump the septic system out to start fresh, then ensure all faucets and fixtures do not drip to cut back on even more water use. A permanent 30 percent reduction in water use may be required to restore the drain field to healthy conditions once it dries out completely if the problem was caused by overuse.

Clogs Caused by Pipe Issues or Compacted Soil

Cracked pipes or pipes damaged or partially blocked by tree roots may also clog the drain field. Replace the pipes to remove the problem. If the pipes are in good shape but partially clogged, contact a company that can flush them out with high water pressure to break up the silt and deposits within. Flushing also helps reduce an overabundance of bio film, a layer of bacterial slime that, when healthy, makes the septic system function properly. Too much of it may cause a sludge buildup that affects the flow of water to the drain field, causing clogs.

If the soil is too compacted to allow matter and water to flow through with ease, soil fracturing may cure the issue. Septic companies have equipment that can pump air down through narrow holes 3 to 6 feet deep, breaking up the soil. Polystyrene pellets are added to the holes to help keep the soil from compacting again.

Treatment for the Drain Field

Some companies offer a nontoxic treatment that is added directly to the distribution box. This type of treatment reacts chemically with the buildup in the drain field, releasing oxygen and breaking up compacted soil. This helps restore the healthy bacteria in the septic field, resulting in improved drain field conditions.