How to Construct a Washing Machine Drain Field

drain field
What You'll Need
Drain pipe

Instructions on how to construct a washing machine drain field are fairly straightforward and easy to follow. Nevertheless, there is some debate about the efficiency of washing machine drain fields, with some research revealing that a washing machine actually works better when the washing machine is plumbed into the septic system due to colonies of bacteria being available to disperse biodegradable matter. However, many homes do still incorporate a drain field for their washing machines. The steps below provide the instructions on how to construct a washing machine drain field in an efficient manner.

Step 1 - Site the Drain Field

The waste from the washing machine contains dirty water as well as detergent so, for that reason, it is as well not to place the drain field too close to plants and especially not a vegetable garden. However, recycling this water to provide water for a flower garden would be ideal as long as the drain field is at least three feet away from the plants so they don’t come to any harm from the detergent in the water. You also need to site the drain field a minimum of two feet away from the house and preferably up to five feet if possible.

Step 2 - Prepare the Drain Field

drainage ditch in a yard

Dig a hole for the drain field at least four to six feet deep, approximately two feet wide and at least 20 feet in length. Larger families who rely on more laundry would probably need the drain field to be closer to 25 feet in length.

Once the hole has been dug a layer of gravel needs to be placed at the bottom of the drain field. The level needs to be at least two feet thick. Then, on top of this layer of gravel, lay between one and two inches of sand or straw. This will prevent waste particles from the dirty water from seeping down into the gravel and causing bacteria to grow.

Step 3 - Install the Drain Field

You need to perforate holes in a drain pipe and lay it the length of the hole: a 20 foot pipe for a 20 foot hole, or 25 foot pipe for a longer hole. Once in position, the perforated drain pipe needs to be completely covered with gravel and the drain pipe that removes the water from the washing machine needs to be fitted to one end of the drain pipe.

Step 4 - Make Sure it All Fits

When you connect up the two pipes you need to ensure they fit together well to avoid water from your washing machine from leaking out. The drain field now needs to be refilled with the earth that was previously removed when digging the hole and, two weeks later when the earth has settled, top the sunken area with more earth until it eventually reaches the state it was prior to digging the hole for the drain field.