Portland / Vancouver Metro - The Dalles - Hermiston OR & Tri Cities WA

What is a Drainfield?

Drainfield Install And Repair in Portland OR, Vancouver WA, and The DallesA septic drainfield, also known as a leach field or disposal field, is an underground system consisting of leaching chambers or perforated pipes where wastewater from the septic tank is treated then absorbed into the soil.

How do Drainfields Work?

A series of shallow and narrow trenches are filled with a network of perforated pipes and a filtration media like gravel or a series of chambers called infiltrator chambers or leaching chambers. This filtration media is to help maintain the structure of the trenches along with providing an additional filtration layer.

Types of Leach Fields

The way a drainfield works depends on its design and since there are various pipe connections and layouts there are different designs. Here are the most common variations.

  • Equal Distribution Drainfield: This is the most common variation Speedy Septic uses. This drainfield is designed to send equal amounts of effluent from the distribution box to a single pipe or multiple pipes connected to the distribution box. This process will help keep the soil from becoming oversaturated as effluent enters the drainfield.
  • Serial Distribution Drainfield: This system is designed so effluent flows from the distribution box to one pipe and trench until it is fully used, then to another. This drainfield works best on a sloped property.
  • Dual Drainfield or Alternating Drainfields: This drainfield system involves two series of trenches but only one is used at a time while the other essentially rests. A valve must be flipped to send effluent to the second leach field.


Also important to mention is the biomat. This black, jelly-like living organism is made up of anaerobic bacteria and is formed when a drainfield is in use. A biomat is a very important part of a drainfield because it creates an additional filtration layer made of living organisms that can further breakdown any particles that enter the drainfield while also decreasing how fast wastewater permeates the ground.

How Do You Know if Your Drainfield is Failing?

Because septic bacteria can be unsafe for humans and pets, it is important to contact a professional if you suspect your drainfield is failing. Below are the signs you may have a failing drainfield:

  1. Wet spots on your lawn
  2. Greener grass where the drainfield is located
  3. Sewage odors in your yard
  4. Your plumbing is backing up

Leach field draining issues can be caused by a number of factors including plugged lines, failing septic tanks, and settling. A Speedy Septic technician will be able to quickly determine the source of the problem and repair your drainfield quickly.

Is it Okay to Build Over a Leach Field?

It’s not recommended to build or even drive a heavy vehicle over the leach field. You should also avoid planting any trees or shrubs as roots may grow into the distribution lines or septic tank.

Experts in Drainfield Installations and Repairs

Whether you own a home or a business, your drainfield design will be determined by the amount and condition of your soil. So if you need a new drainfield or need repairs to your existing leach field, contact Speedy Septic today! We also provide emergency services!
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Drainfield Install and Repair in Portland OR and Vancouver WA

Also Serving Customers In These Regions

Portland Vancouver Metro
Portland OR | Gresham OR | Troutdale OR | Sandy OR | Cascade Locks OR | Clackamas OR | Happy Valley OR | Oregon City OR | Canby OR | Molalla OR | Beaverton OR | Hillsboro OR | St Helens OR | Scappoose OR
The Dalles
The Dalles OR | Hood River OR | White Salmon WA | Bingen WA | Parkdale OR | Mosier OR | Biggs Junction OR | Dufur OR
Hermiston OR | Arlington OR | Boardman OR | Umatilla OR | Irrigon OR | Pendleton OR | Tri-Cities WA | Kennewick WA | Richland WA | West Richland WA | Pasco WA