Laundry to Landscape
Laundry to Landscape (L2L) systems are one of the most common and effective greywater installation options. By connecting your washing machine to outdoor piping, you can irrigate your landscape with gently used water.
L2L systems require little maintenance once installed, but there are a few factors to consider before and during use. L2L systems work best with simple irrigation systems, as the particles in greywater tend to clog drip irrigation systems. L2L also work best for large, well-established plants, as it is more challenging to water many small plants with a simple irrigation system. Using biodegradable, non-toxic detergents is also crucial with a L2L system. See Greywater Action's FAQ page for more information about L2L systems.
Exterior Wall Systems
If your washing machine is on an exterior wall, installing a L2L is relatively straightforward. The general process involves drilling a hole for the greywater pipe to connect to any irrigation system. See Greywater Action's page for specific guidelines on installing an exterior wall system.
Interior wall systems
Installing a L2L system is more complicated if your washing machine is not located on an exterior wall. The greywater must first be sent under the floor first before being directed outside. See Greywater Action's page on interior wall installations.
The Do's and Don'ts
Label: Greywater pipes need to be clearly labeled, especially PVC pipes, to differentiate them from potable water pipes.
Build it Big: Oversizing your system allows for the unexpected. A sudden surge in water use can be contained in an oversized system.
Use the 3-Way Valve: If using bleach in system, washing cloth diapers, or if you notice pooling in your system, turn the 3-way valve from greywater to septic or sewer.
Bleach: Do not use bleach when greywater system is turned on.
Drink: Greywater is not safe to drink or wash with.
Root Vegetables: Do not allow greywater to come into contact with edible portions of food crops.
Spray: Do not distribute greywater through sprinklers.
Hang on to it: Greywater cannot be stored safely for more then 24 hours. Don’t try to store it until summer, you will have blackwater (septic) water in your tank, not greywater.
How to Size Laundry to Landscape Irrigation:
1. Determine your water need:
Count existing plants that need water, making note of the flow rate of rrigation emitters if present.
If there are no emitters, make a best guess estimate by counting how plants are being water by hose or sprinkler.
Count new plantings, if any, and add up their water need.
2. Estimate your greywater flow:
Calculating wash water output: find the outlet hose of the washer and place it in a large container, such as a trash can. Run a normal wash load, filling up your container.
Old top loading washers produce up to 50 gallons, so make sure you have a large enough container to capture all that water!
Determine your soil structure and soil type.
Conduct a Percolation Test.
Greywater Irrigation Sitting Considerations:
Consider where you want the greywater to go. It is ideal to use gravity to your advantage. Your washer can only pump up above the washer by 6 ft., any more and you may burn the pump out. Gravity fed systems tend to last the longest, and all around are usually better.
Do your soils have good percolation? Make sure to perform an infiltration (perk) test to see if the water will infiltrate your soils so that no pooling of greywater happens.
Know your setbacks. Each area has different setback distances.
Here is an example of California greywater setbacks:
Building Foundations: 2 feet
Property Lines: 1.5 Feet
Water Supply Wells: 100 Feet
Streams and Lakes: 100 Feet
Water Table: 3 Feet Above
Retaining Wall: 2 Feet
Having too steep of a slope can cause problems with greywater. Make sure you have less than 20% slope.
When Not to Use Laundry to Landscape:
Very poorly draining soil.
Difficult to access drainage pipes.
No room for plants and trees.