Drain Fields

An underground storage area to allow liquids from primary treatment or graywater to soak into the ground.  Typically a soil covered, stone filled pit with perforated distribution pipes.

Treatment Level:  Secondary
Relative Cost:
Amount of Maintenance Interaction:  low
Beneficial Byproduct:  none


  • Very little maintenance needed.
  • Nutrients and water source are beneficial for healthy ground cover over the field.
  • Groundwater recharge.


  • Takes up a lot of space that cannot be built upon.
  • Success depends on ability of soils to absorb water.
  • Not suited for areas with high groundwater, lots of rock or clay, or within a 50 ft radius of drinking water source.

Operation & Maintenance

  • Inspect for ponded water on surface.
  • Inspect the primary treatment measure to ensure that solids cannot migrate downstream.
  • Typical life of a drainf ield is 50 years.  If it fails, it must be relocated or replaced with an alternative technology.

Additional Notes:

  • Best to keep stormwater drainage directed away from the drainf ield as much as possible.
  • Important not to compact the field with heavy equipment or impervious surfaces.

Drain Field Distribution System (www.jeffreyedwardsllc.com/pics)