The longest lasting, lowest-maintenance, most ecologically sound systems will not require a pump. If you can, use gravity to irrigate with your greywater! Make sure your system truly requires a pump before deciding to use on.
These situations do require a pump:
- The only landscaped area needing irrigation is uphill of the greywater sources.
- There is a long flat area of hardscape that must be crossed before reaching the landscape.
- The yard is flat and the only irrigation needs are far from the house.
If you have to use a pump, look at the closest places you’ll need the water and then pump the greywater there. You never want to pump more than you need to (ie. don’t pump to the top of your property, or to your roof) If you pump to a high point and then gravity drain to the yard, it uses extra electricity and will be harder to control the flow of water to the plants. Pumps pressurize water and make it easier to spread the water out to plants; this benefit is lost if the system switches to gravity flow.
How to Choose a Pump
Look for an effluent pump that’s rated to pump 3⁄4″ solids (so it can pump out anything that gets down the drain), is fully submersible, and operates on 115/120-volt (not 230/240-volt) electrical power. A typical sump pump is not powerful enough for this system. Some people use smaller-sized pumps, rated to pump 3 ⁄ 8 ” or 1⁄2″ solids, though they aren’t as strong as 3⁄4″-rated units.