Domestic Greywater Irrigation System

View of the holding tank containing the pump

In an attempt to solve three problems:

  1. Save water being wasted down the drains
  2. Keep the garden watered in summer
  3. Extend the interval for the septic tank being emptied

I built a system to divert the bath/power-shower and washing machine water, so called greywater (or graywater).

Next time you have a power shower, assuming it's an in the bath type installation, put the plug in and see how far it fills up. It can take as much water as a bath would.

This picture shows the 25 gallon tank used to hold the greywater until it can be pumped out over the garden. You can see the white pipe feed in at the top of the tank and white overflow exiting from the front. The black pipe is the pump outlet to the distribution pipes.

Pump and filter inside the tank

The picture to the left shows the pump with an integral float switch and the filter to keep hair out of the pump

Connection between the ground pipe and garden hose

The water is distributed under ground via standard MDPE 25mm plastic pipe and then connected at strategic points around the garden to either soaker hoses or ordinary hose pipes with small holes lined up with key plants, 50m in total. This picture shows such a connection.

So far it has been very successful, it has already paid for itself. It doesn't cause flooding in the garden even when it has been raining heavily. Some of the hedges have really plumped up. The septic tank emptying interval has gone from 2 months to more than 27 months! The only time the overflow has gone into the septic tank was when we had snow on the ground.

Curiously this page has had the most hits of our web site. So I would be interested if others have tried this or have any questions about my installation.

Steve Brown © 2001-2015. All rights reserved