Introduction: Laundry to Landscape Greywater System

***Edit May 2017: While this instructable was written with the best information I had at the time, greywater design and best practices have moved on. The best designed L2L systems now use 1" reducing tees instead of the drilled emitters detailed below. Also there should be a 1" fail safe overflow (no plug at the end). This saves washer pumps if the emitters become clogged and no maintenance is done. For those wanting more information on L2L systems, I recommend Laura Allen's new book 'Greywater, Green Landscape.' It's great. If there is a lot of interest I may revise this instructable.***

This design and much of the information contained within are borrowed with permission from Art Ludwig's website: The Laundry to Landscape greywater system was developed by Art Ludwig of Oasis Design and published unpatented into the public domain for all to use. If you want to spread this information please credit and link back to the information hub for updates on the Laundry to Landscape system. The Oasis website has 100 pages of more in-depth information and alternative designs for greywater, water storage and composting toilet systems. I highly recommend that you visit that site and donate via their tip jar so that they can keep designing for the public! Oasis also publishes the definitive book on greywater and instructional DVD on the Laundry to Landscape system.

Help me make this instructable better by commenting!

What is greywater?

Greywater is wastewater, excluding human waste, from your home that you can reuse, in this case to irrigate landscape. Greywater is wonderful for many reasons, including:

* Reduced freshwater use

* Reduced chemical and energy use from conventional wastewater treatment

* Effective treatment in soil

* Groundwater recharge

* Reclamation of otherwise wasted plant nutrients

A greywater laundry system is an easy and affordable way to implement this technology in your own home. According to the EPA, 21% of the average american home's indoor water use is with a clothes washing machine, so it's a significant amount of the water.

Greywater has been legal in California since 2009. Laundry systems that follow certain requirements of the plumbing code don't require a permit, but your municipality may have additional restrictions.

Before implementing greywater, consider doing easier and cheaper water conservation measures: fixing leaks, installing low flow fixtures, changing habits, etc.

Step 1: Site Analysis and System Design

Spend some time looking at your site and determining what plants you want to irrigate. Matching your greywater system to existing irrigation zones means you'll be able to dial back that area's irrigation or turn it off completely to realize water savings.

The washer pump can handle moving water any reasonable distance downhill, or up to 2' below the top of the washer 100' away. Perennial plants like fruit trees have more established root systems and are more able to find the water easily. Non-root vegetables can be irrigated with greywater if the emitter is close enough to the plant. They usually will need supplemental irrigation during establishment.

Having your washing machine in a room with an exterior wall is ideal.

Step 2: Tools and Materials

This system can be made of PVC or alternatively of HDPE. HDPE is a more environmentally friendly material. Materials can be purchased online or maybe at your local hardware/irrigation supply store. The 3 way valve is most easily found online.

Tools (Top to bottom):

Hair dryer


Pipe cutter (a saw works too)

Screwdriver (or socket driver, for hoseclamps)

Large adjustable wrench

1 1/4 spade bit or hole saw (use the right size for your pipe, this may vary)

3/8" or 1/4" drill bit

Oops, forgot the shovel

Oops, forgot the knife

Materials (will vary):

(1) 3/4" Brass diverter valve

(3) 3/4" MPT x 1" barb

#12 Hose Clamps

1" HDPE pipe


(1) 1" barbed tee

(?) 1" barbed elbows (for making sharp turns outside or neat turns inside...not shown in materials because I used them all)

Pipe brackets

Drywall anchors or screws for pipe brackets

Irrigation goof or bug plugs (if your emitters are 7/32 drilled holes)

Teflon tape

Garden hose gaskets

Hose Service Connection:

1" barb x FHT (Female Hose Thread)

1" barb x MHT (Male Hose Thread)

Vacuum Breaker: There are several ways to do this...discussed later


Step 3: Components of the System

The next steps will take you through each piece of the system. Rather than showing one complete installation, I've chosen photos from several different ones to best show what's being illustrated.

Step 4: 3 Way or Diverter Valve

This valve lets you divert greywater from your washer to either the landscape or the sewer. You want to send the greywater to the sewer if:

*You're using a greywater incompatible soap or bleach

*You're greywater system is broken, abandoned or being maintained

*You're washing diapers

For this valve, the washer always connects to the bottom, which is 'always open.' The handle switches that flow from the going either to the left or the right.

Locate the valve so that it's accessible to the user. I've shown a few different installations. Either between the washers or above them makes sense to me, depending on how hard the owner loves the look of the valve. Use several pipe straps to anchor the valve assembly to the wall.

Step 5: Washing Machine

Clamp the drain hose to the 'in' of the 3 way valve. You may have to modify the drain hose. Sometimes the hose can be clamped directly to a 1" barb fitting, sometimes not. The drain hose might have a pint of stagnant greywater in there, so empty that into a bucket so it doesn't drain onto the floor while you work.

Step 6: Pipe to Sewer and Working With the Pipe

Run one side of the pipe from the 3 way valve to your sewer standpipe.

Tips for working with the pipe:

1) Use a hair dryer to expand and soften the pipe if it's hard to put on barbs.

2) The pipe will want to coil up. This is shitty. Leaving the pipe in the sun will make uncoiling it easier. It can be persuaded to make other shapes, but it's not that fun. Work with the curve rather than fighting it when possible.

3) I use the adjustable hose clamps. There are also crimp style ones that are cheaper, but the crimper tool is expensive.

Step 7: Vacuum Breaker

The purpose of this component is to prevent a siphon from forming when the washer is filling. It should be placed at the highest point in the system. This can go inside or outside. Preferably outside as it is a potential source of leaks.

I've done this two ways:

1) with a spring check valve (the white fitting) and appropriate barb adapters.

2) An irrigation air relief valve. I don't trust this to not leak, so locate this kind outside. It's substantially cheaper than the check valve.

You may be forced to locate the vacuum breaker indoors depending on where the washer is located in the house.

Step 8: Wall Transition

Warning! There are all kinds of things in walls around washer systems: high voltage electrical, gas lines, sewer lines, sewer vents, water pipes. Spend some time and think about what you're doing. Turn off the power at a breaker. If you're not sure, stop.

Make a hole slightly larger than the diameter of your pipe and insert the pipe. On the outside wall, Seal the penetration with caulk. I like to use a pipe collar as trim. These are at hardware stores near the faucet section.

In one of these systems, I went out the window. This may be a good option if you're a renter and the window is well protected from weather. In that installation, residents were already using the window to vent the dryer. I'm going to make a redwood insert for the window to better seal it up.

Step 9: Hose Service Connection

This allows for lint, hair and muck to be flushed from the system using a garden hose when you need to do maintenance. Put the male fitting upstream so that the garden hose can thread in there.

1"Barb x MHT

1"Barb x FHT

Step 10: Backflow Preventer (optional)

It's for if you're planning on pumping the greywater uphill. Beware burning out your washer pump doing this. Use a swing check valve. I haven't installed a system that has needed this.

Step 11: Pipe to Landscape

Shallowly trench where you want to irrigate. In heavily mulched yards, sometimes you can bury the pipe in the mulch and skip trenching. You can tee your line, but don't go overboard. I wouldn't tee more than once or twice. Smaller runs of pipes, especially with the ultra high efficiency washing machines will be more successful. Use heavy things to anchor your pipe until you backfill.

Step 12: Outlets

I generally drill my own holes because the irrigation pipe is cheaper and easier than the alternatives. Consult Oasis Designs chart in their calculator spreadsheet for the number and size of emitters to drill. Too many or too big of holes and some areas along the pipe will be dry. Too few or too small of holes will cause wear on your washer's pump.

Step 13: Outlet Shields

The purpose of the outlet shield is to leave an air gap between the hole in the pipe and the soil/mulch. This helps delay the intrusion of roots, and makes finding the 'emitter' locations easier.

These shields were made from repurposed nursery pots. Pots made of thicker plastic tend to work...those made of thinner plastic are too flimsy. This example could have been cut so that the pipe runs higher off the ground. Experiment with a few pots and see what works for you.

I've heard of other installers abandoning this method in favor of other methods. Please post your favorite solution in the comments.

Caution: Don't cut yourself.

Step 14: Seeing If It Works

Attaching a garden hose to the hose service connection, you can dial in the system without having to clean all the neighbors' undies (ie having to wait for the washer to pump).

Confirm that water is coming out of each emitter. You may have to play around with leveling pipes or adding or subtracting 'emitters' to get this right. Using 7/32" holes allows for drip irrigation goof plugs to be used to plug emitters if you've ended up with too many.

I recommend running at least one load and switching the valve from landscape to sewer and back during pump out to check for leaking connections.

Using Oasis' chart for sizing and number of emitters, I haven't had to work very hard during this step.

Wait to backfill until you've finished this step.

Step 15: Use and Maintenance

Only use laundry soaps that are sodium and boron free. Check the ingredients. Oasis and Biopac brands are developed specifically for greywater systems.

Be sure to use the diverter valve when using bleach or an inappropriate soap.

Observe your plants for salt damage and drought stress.

Approximately every year, flush your system of lint and hair buildup using the hose service connection. Use the outlet chambers to see that the emitters are not clogged. Clear if clogged.

Step 16: Celebrate! You've Done It!

Washing your clothes will never be the same.

Step 17: Shameless Plug

I am a greywater system installer operating in the Sacramento/Davis area. I also design and install green roofs. Check out my website here.

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