Greywater is showers, tubs, bathroom sink, and laundry water. RO discharge and AC condensate can be allowed. Greywater contains nutrients that plants love. In California, there are two types of greywater irrigation systems, untreated and treated.

Untreated Greywater Systems

Untreated greywater systems have been available since 1990 and have been legal in all California since 1994. Because they use greywater beneath the soil surface in drip irrigation, they are extremely efficient at irrigation and are the only type of graywater system to mitigate PFAS and endocrine disrupters abundant in greywater.

ReWater’s untreated greywater systems are the only untreated graywater systems proven from decades of real-world experience to not clog over time. That’s because our systems 1) use a proven sand filter method orchestrated by our proprietary controllers, and 2) use our patented emitters that aren’t susceptible to the long term “scaling” created by greywater.

Treated Greywater Systems

Treated greywater systems that are NSF 350-approved have been legal in California for certain applications since 2016. “Treated” is the legal term for greywater that has undergone an extremely expensive treatment process that reduces biological pathogens in greywater.

That treatment process does not solve the downstream “scaling” caused by even highly treated greywater. This process also does nothing to mitigate PFAS or endocrine disrupters.

Some claim a NSF 350 stamp of approval means the system will work long term. But the NSF 350 laboratory test didn’t include hair and lint found in real greywater nor did it consider the long-term effects of downstream scaling when combined with the minerals in tap water.

Greywater’s Microscopic Solids

Even finely filtered and treated greywater contains microscopic solids that combine with the minerals in water to form a visible “scaling”, a lining, on the inside diameter of pipes, valves, and tubing. That’s the visible “grey” in greywater.

That lining builds up until it flakes off over time due to water flow. Those flakes are well known in the irrigation industry as “scales”, which flow downstream to the tiny orifices found in every irrigation emitter but ReWater’s. Once a “scale” has lodged in an emitter’s orifice, there’s no way to unclog it. Plants deprived of water start wilting, then dying. Eventually the entire drip irrigation system has to be replaced.

The Inevitable Failure of the Wrong Emitters

It’s not a question of if emitters made for fresh water or municipally treated wastewater will clog from greywater’s scaling, but how long it takes those emitters to clog. The industry average is two years, long enough to beat most landscape installation warranties. Some emitters don’t last that long and some last longer, but they all clog eventually. They are simply the wrong emitters for greywater.

The Only Greywater System That Works

ReWater’s cost effective greywater systems have been proven to work for over three decades in landscapes at homes, apartments, barracks, everywhere untreated greywater is found. Of course they work with rain as well.