Drip irrigation tubing has very small emitters, which will quickly clog from particles in greywater. To use successfully use greywater in a drip irrigation system you’ll need to:
- Filter it.
- Have a plan to clean the filter (either automatically or by hand).
- Employ “greywater compatible” drip irrigation tubing.
Keep in mind that greywater filters do not remove salt or other chemicals which may harm plants, the filters remove particles to prevent clogging of outlets. There are two ways to filter greywater: manually cleaned filters and automatically cleaned filters. Manually cleaned filters are lower in cost than automatically cleaned ones, but require frequent maintenance, and thus are often the cause of system failure or abandonment. (Most people find it tiresome to clean a yucky filter month after month, year after year.)
For a long lasting system, it’s best if the filter is automatically cleaned. These self-cleaning filter systems are usually connected to the potable water supply so the pressurized water can “back flush” the filter. Having this connection to the potable water supply creates the potential for “cross contamination” (greywater being sucked back into the potable water from a drop in city water pressure) so a “back-flow preventer” is needed. This adds increased cost and regulatory oversight to the system.
If you want a filtered, drip-irrigation, system we recommend getting a maintenance contract with an installer when ever possible.
There are a few manufactured systems designed to use greywater in a drip irrigation system. See the Manufactured Systems page for more details.