(Back to Irrigation Methods)
To avoid adding work load to a washer machine pump, and still be able to irrigate up hill or some distance away from the washer machine, an additional pump can be used inside a container (eg barrel) to move the water where it is required.
In most jurisdictions, aeration of water is prohibited. This is because there is potential for water mist generated by a high pressure pump / nozzle to be blown to a neighboring property, spreading illness that may be contained in the graywater.
Medium pressure pumping systems connected to a hose with an adjustable nozzle are very popular, especially in Australia, despite being in contravention to regulations. With only medium pressure water passing through the nozzle, the droplets of water are large and heavy, and will not be blown to a neighbouring property in normal wind conditions.
People appear to make their own risk assessment and apply common sense. Some jurisdictions have recognised this and are now redefining their regulations to exclude misting of graywater, implicitly allowing the use of nozzles that only form large droplets.
- Low Cost, systems such as the irrigation barrel can be found for around $280, or if you have your own barrel a graywater capable pump and hose kit is available for around $180.
- DIY installation.
- Performance, graywater can be pumped up to 120' distance while still maintaining decent nozzle pressure. Graywater can also be pumped 40' up hill.
- Graywater is irrigated where required. Gravity based systems (or washer machine driven irrigation) do not irrigate evenly unless much time and effort is spent tuning emitters, and committing to ongoing maintenance to remove lint build up.
Using a graywater dripperline system with a washer machine re-pumping system
- Aeration of graywater may be prohibited in your area.
- Plants should not be top watered in the heat of a summer day, because of sunlight effects through droplets of water on the plant. Instead, graywater should be stored until the end of the day, and then irrigated.
- This method should only be used for washer machine water. Shower water can develop unpleasant odors very quickly (within an hour in summer) if stored in a container. Storing shower water until the end of the day and then watering is best avoided.
- Although far easier (and safer) than bucketing graywater, this method still requires manual intervention (storing graywater until the end of the day, walking around with a hose etc).
- Herbs and vegetables should not be irrigated with graywater from a hose unless they are cooked (killing any bacteria that may be in the graywater).
If the washer machine water is the only accessible graywater in the house, combining a repumping system with a graywater dripperline system (refer here) produces superior results without requiring professional installation:
A comment on California's new emergency graywater provisions
- Graywater is irrigated evenly across the entire garden area.
- DIY installation
- Economical, total cost of all parts is approximately $650.
- Automatic, every time the washer machine runs, the garden is watered.
- Vegetables and Herbs can be irrigated (refer to more information about vegetables and graywater here)
California has made significant improvements to its graywater regulations, having recognised that graywater re-use should be encouraged, and that washer machine water can be accessed without requiring a plumber.
Essentially the State now allows a graywater irrigation system to be installed without a permit if the following applies:
- Graywater is only taken from the washer machine
- The irrigation system must be sub surface.
- An additional pump must not be used.
In our opinion this is poor policy. It encourages the use of 'Laundry to Landscape' irrigation, using the washer machine pump to pressurize hoses or similar to irrigate the garden. Apart from damaging the pump, pooling of graywater is likely - the least desirable of all graywater irrigation methods.
You can read our opinion of 'Laundry to Landscape' here.
Further information about Irrigation Methods
Irrigating every day
Buckets and hoses
Laundry to landscape