How to Build a Cheap Greywater System

The easiest greywater system makes use of washing-machine discharge.

Greywater refers to water that's been used for washing dishes, showering, laundering and similar tasks. The water is not necessarily literally gray, but has been used in some way in the home. Greywater can be recycled for certain uses such as watering the garden or lawn. Certain kinds of water are unfit to use again and are considered to be blackwater. Blackwater is water that's been used in the toilet or garbage disposal. It should not be recycled, but must go into a septic tank or sewage system.

Step 1

Install a diverter valve in your washing machine's drain line. The easiest way is to cut the line at a convenient place, fit the diverter into the line and clamp it down. This allows you to send water outside or into the septic tank or sewer system.

Step 2

Make a circular basin around each plant or area to be watered with greywater. Use bricks, pavers or anything else you like to create basins that will contain the greywater when it discharges. Using recycled materials will help to keep your costs low. The edges should be at least 6 inches high.

Step 3

Fill the basins with mulch. This will help absorb the water, to avoid large puddles and keep the soil damp for long periods.

Step 4

Create the greywater line from the washer to the plant basins. Attach the connector to the unused opening on the diverter. Drill a hole in the wall with the keyhole saw near the washer drain, and feed one 2-foot section of PVC to the other side of the connector. This piece should come straight out of the wall. Caulk around the hole to prevent pests from getting in.

Step 5

Place the "T" piece on the outside portion of the PVC. Attach one 10-foot section of PVC to each side of the "T." Direct the other end of the PVC into two separate mulch-filled basins and cement all the pieces of PVC together to complete the greywater discharge system. Note that you may need to adjust the pipe lengths used to fit your yard and home.


This greywater system is best for trees, bushes and other large plants. It also works best when the plants are at the same level or below the level of the washing machine. The action of the washer will force the water through the system and out to the plants.

Things You'll Need

  • Diverter valve for 1-inch pipe

  • Hose clamps

  • Bricks or pavers

  • Mulch

  • 1-inch PVC pipe connector, diverter to pipe

  • 1-inch PVC “T” connector

  • 1-inch PVC pipe, 2-foot section, 1 piece

  • 1-inch PVC pipe, 10-foot section, 2 pieces

  • Caulk

  • PVC cement

  • Keyhole saw, 1-inch


Use environmentally friendly laundry detergent so that it will break down naturally when it reaches your plants. If you use bleach, switch the diverter to send the water to the septic tank or sewer instead of out to the garden where it may do harm. Check your local zoning and health regulations to see if a greywater recycling system is allowed in your area. Some areas restrict or prohibit the use of such systems.