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DIY: How to Build a Greywater Recycling System in 3 Steps


greywaterdiy3Water shortages already cause problems for millions of people around the world, and the problem will likely only be exacerbated in the future. Get ahead of the curve and start saving water now by building a grewyater recycling system.

These systems divert water from the shower or sink to an outdoor tank which can then be used for watering the garden. This project is fairly easy to complete by following the three steps below:

1. Finding the Right Flow

The first step is to map the plumbing to find where to place a diverter pipe. Using the shower or bathtub will provide the most water, so choose these locations for the greatest return on investment.

In most houses, there will be a pipe that runs from the bathtub or shower down to the sewer. In the schematic below, a pipe connects the bathtub to the shower pipe. Installing a valve and diverter pipe will ensure that all the water runs to the greywater tank.


2. What You’ll Need

  • Covered rain barrel
  • 2″ PVC ball-valve
  • 1/2″ I.D. PVC pipe, with corner fittings for diverter pipe
  • Standard garden hose tap
  • 1/2″ drip irrigation black connector hose
  • ABS-PVC cement
  • transition cement

3. How to Build the Systemgreywaterdiy4

The 2″ section of ABS pipework that includes the U-bend can probably be detached, which will make this process much easier. Remove a piece of the pipe so that there is a hole the same size as the inline length of the ball valve. Make a PVC collar out of a butt joint piece and drill a hole for the 3/4″ pipe. The ABS pipe will also need a 3/4″ hole so that the collar can fit over the ABS pipe with the holes aligned. Glue the PVC collar to the ABS with ABS-PVC cement. Insert a PVC right-angle joint into the hole with transition and PVC cement and glue the ball gag with transition cement. Then, re-fit the the new assembly to both the bathtub drain and the plumbing.









Run the irrigation hose from the tap to the lid of the barrel. The ball valve can then be opened or closed, diverting water to the tank or to the sewer. This great greywater recycling system can also be used to trap rainwater. More information on this project is available here.

Images (c) Instructables user adaviel

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