There was a time, not so long ago, when greywater systems were not allowed in some municipalities. Even today, they are regulated. Long-running droughts have, of necessity, made the installation of greywater systems not only legal but desirable. Greywater is the water used in your washing machine and in your bath for bathing or showering that otherwise goes down the drain and to waste. Diverting the flow of this water through a pumping system to irrigate your landscaping is a great water conservation method.
According to Save the Water:
“Gray water” doesn’t refer to the color of the water, but the level of purification that happens before we use it.
We start with potable water, suitable for drinking. After we use that water to do laundry or bathe, it is considered greywater. Once we use potable water to do dishes, or mop a floor using harsh chemical cleaners, that water is considered more contaminated and referred to as blackwater and is unsuitable for use in grey water systems. Water which has feces or sewage in it (think rinsing baby diapers) is blackwater. Differences of opinion may exist when it comes to dishwater, as some people feel that the organic matter contamination is minimal, while others consider it to be contaminated blackwater. In Marin, dishwater and water from a dishwasher are not classified as greywater and are not included in a greywater system.
A greywater system can also be augmented by a rainwater collection system, or they can both be stand-alone options.
Greywater-Ready New Construction
Greywater-ready new construction may be the wave of the future. A Marin IJ article (3/2/2022) stated:
The county and Marin’s cities and towns are required to build a combined total of 14,210 new housing units by 2031; that is six times larger than the number assigned by the state for the previous eight-year cycle.
Opponents of the mandate worry that development on that scale will threaten Marin’s precarious water supply. Planning for the growth of greywater systems could help to mitigate the problem.
Homes constructed with greywater system hookups already installed will make it easier for homeowners to complete the system in the future. They can become an additional selling point for green-minded buyers. Developers, architects and builders can include greywater-ready plans following current statewide and municipal ordinances/guidelines. In fact, state and municipalities can require this readiness to promote residential and commercial greywater systems.
Greywater and Remodeling Projects
As with anything else, making sure new homes are greywater-ready is easier than adding a system to a remodeling project. Still, there are a number of sites that offer D.I.Y. options, a book and plenty of YouTube explainer videos. You still might want to have a trusted plumber as a back-up, since older homes sometimes present problems you just can’t see until you get inside a wall, or deep into the crawlspace.
This post first ran in 2022.