What Is The Difference Between A Pit And A Field?
As a homeowner with a septic system, you may be curious about how the system works and what its components and setup are like. Some older septic systems were built with a seepage pit rather than a leaching field. Understanding the difference between these effluent processing systems can help you to ensure that your septic system gets the maintenance it requires.
Seepage pits are dug vertically into the ground to collect the gray and black water from a septic tank. The vertical orientation of a seepage pit is the most important difference between it and a leaching field. Most seepage pits are built so that at least four to six feet of soil covers the top of the pit. Because the pit is buried so deeply into the ground, most of the waste water processing is done by anaerobic bacteria. The seepage pit is made of poured or cast concrete and is surrounded by rocks so the waste water can percolate into the ground after processing. Seepage pits are more strictly regulated than leaching fields because less processing of the effluent takes place. If a seepage pit fails, the untreated waste water will flow back into the residence.
Leaching fields are arranged vertically and buried about three feet below the surface of the soil. The leaching field consists of an array of perforated pipes that allow processed waste water to slowly percolate into the soil where it is further processed by bacteria. The pipes of a leaching field are typically made of PVC. If a leaching field fails, the water most often builds up in the surrounding area, causing mud or ponding of water to develop above the location of the leach pipes.
Caring for Seepage Pits and Leaching Fields
A seepage pit requires regular inspection and pumping so the biomat at the bottom of the pit does not become too thick and prevent the permeation of treated water into the soil. Every three to five years, the seepage pit may need to be pumped. With a leaching field, the septic tank that it is connected to requires similar maintenance as a seepage pit. The leaching field’s septic tank should be regularly inspected and checked for scum and sludge buildup as well as for blockages in the leaching pipes.