What is Greywater?
Greywater (or Gray Water) is defined as any use of the discharge water from sinks, showers, baths, and laundry machines for watering in the landscape. This excludes water from kitchen sinks, water used to wash diapers, or any water which contains a significant amount of fats, oils, grease. or fecal matter.
Do’s and Don’ts of Greywater for Laundry:
- 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 moreqthen 24 hours. Don’t try to store it until summer, you will have blackwater (septic) water in your tank, not greywater.
Best Uses for Laundry to Landscape Greywater:
Using laundry water for irrigation has many advantages over irrigating with other types of water (i.e. shower water, rainwater). Laundry greywater systems have a built-in pump in the washer. This means that laundry greywater can be pushed horizontally or even slightly uphill. Utilizing flexible poly-line, Laundry greywater systems have a flexibility that makes them great systems for those new to water reuse. If a system is installed and later needs adjustment, these irrigation lines can easily be dug up and re-routed. Also, laundry water carries nutrients (skin cells, soil from clothing...) that plants can uptake and use. This water can be taken to existing plantings, as long as they enjoy be watered in the summer, or can be devoted to new plantings to expand a landscape. Overall, if used wisely Laundry to Landscape systems are fairly cheap, easy, and adaptable way to irrigate your landscape.
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.
- 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 containerNote: It may be easier to use a few 5 gallon bucketsrather than one large container as the water can get pretty.
- 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.
When Not to Use Laundry to Landscape:
- Very poorly draining soil.
- Difficult to access drainage pipes.
- No room for plants and trees.
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.
Calaveras and Tuolumne Permitting Links:
Greywater Laundry to Landscape Troubleshooting Guide:
Greywater Laundry to Landscape Photo Gallery: