Every Brooklyn brownstone should have a gray water system to feed the toilets, green roof, living wall and garden.

Unfortunately there are few systems to choose from. They range between $2,000 and $7,000 for the unit not including running the extra drains from the shower, bathtub, sink and washing machine.

Right now in the US the only only prepackaged residential gray water systems I know of are Water Legacy, Brac Systems, and ReWater. A fourth, produced by Water Saver Technologies, and distributed by Sloan Valve, is also available, but is not a whole-house system. It recycles the water from one lavatory sink for use in the water closet in the same bathroom. It seems to work ok but I’m not crazy about the concept. I rather a whole house system – less parts to break. The price is pretty good. A couple hundred dollars.

Several other systems, currently available in other countries appear ready to enter the U.S. market: Perpetual Water and Nubian from Australia, EcoPlay from the Netherlands, and Pontos (a subsidiary of Hansgrohe) from Germany.

There are a couple gray water systems for the garden. Matala makes a great one called Aqua2use. Waterwise does too. But they don’t work for toilets. Matala is coming out with one soon they say.

I have used the Brac system and they suck. All the other systems are ok but I’m not in love with them. The best is Water Legacy. But like most of them it is costly at $4,500.

Eco Brooklyn is working with an engineer and the Department of Buildings to build our own legal system. But it is slow going. For the time being we are stuck with making our own under the radar systems with early adopter clients. The systems work great and are affordable but they are still very much a work in progress.