Leach Field and Leach Field Problems

Septic Drain Fields / STAs / Leach Fields

Septic Drain fields, also most commonly called Soil Treatment Areas (STA), or the old term Leach Field, are subsurface wastewater disposal systems used to remove contaminants and impurities from the liquid discharged by a septic system.

There are several different types of STA’s in use today. The most commonly used is a series of four-inch diameter Perforated PVC pipe encased in two-to-three foot wide stone filled trenches, with porous material (like gravel or sand) around and underneath the pipe to promote drainage and reduces root growth near the pipeline. A minimum topsoil placement is covered over the porous material to protect contact with wastewater and reduce infiltration from rain and snow.

Cut-away of Septic Drain field/Leach Field
Cross Section of Septic Drain field/leach Field

Having problems with your STA/leach field?

Symptoms of trouble:

  1. toilets won’t flush, or flush slowly
  2. wetness on top of the leach field (Example pictured here)
  3. water standing in inspection or vent pipe from leach field
  4. water or sewage backing up in the house

Wetness on top of leach field

How do you know if it is a STA/leach field problem or a drainage problem?

You can call your septic company (Us: 303-526-5370!) or if you are able and handy, check the level of liquid in your tank.

Using your favorite shovel, pry up the tank lid or lids. The level of the tank should be down where the inlet comes in from the house or on the outlet where the effluent leaves the tank for the leach field. This is about 10–12 inches down from the top of the tank. If the level is normal, (at the bottom of the inlet pipe), you have a clogged line from the house to the tank.  Call us for recommendations if plumbing service is needed!! 303-526-5370

If this level is up to the lid, or overflowing you have an obstructed line to the leach field or a problem with the drainage in the leach field.

Problems with leach fields are a result of many different reasons.

  1. Age of leach field
  2. Engineering or installation problems
  3. Not pumping tank often enough
  4. Compaction problems from parking cars, livestock on top of leach field lateral lines
  5. Spring runoff of water can flood leach fields.
  6. Too much water usage.  Hydraulically overloading the system.  This causes a bio mat to build up in the leach field and the bio mat starts restricting the water absorption in the leach field

If you are on a septic system and your leach field is not draining the way it should, you can replace the leach field if you have room on your property or we have some alternatives listed below.

Leach Field Replacement Alternatives


We have a Terralift machine. We use this over the leach field surface. The machine punches a probe down in the ground 6 ft, then a compressor injects air and polystyrene beads. This fractures the ground and the beads opening up paths for the water to leach back in to the ground. We have had good results with this process. Call us to schedule an appointment to come out for an evaluation. Also check out the Terralift on www.terraliftinternational.com.


Bio-remediation is another possible successful solution. It is a specially formulated bacteria we use on a problem field.  Once injected in the system, it goes after eating up the bio-mat that has accumulated. Find out more at www.propump.com  or we can send you a booklet on the process. Just contact us.

Have More Questions?
Ready to have us help you?

Call us to help with your Leach Field Problems. 303-526-5370