We are installing a gray water system. It is still pretty unknown to most DOB inspectors in NY and Brooklyn.
But it is legal if you use the right system. We got a Brac Gray Water System from their local distributor New Eco.
Here is the info you need if the inspector should raise their eyebrows.
All of Brac’s systems (residential & commercial) are ANSI and IAPMO approved and conform to the International Plumbing Code (2006) Section 301.3 and Appendix C.
Here is another thing of value: a water quality certificate issued by the independent Sodexen society in Canada.
A tank costs around $4000. Then you have to run separate drain pipes from all the showers, tubs and bathroom sinks to the tank. You also need to run lines from the tank to feed the toilets with the gray water. So it is something you really want to do during a full renovation. You can also run a line from the tank to your garden. If you avoid toxic cleaners like bleach etc then the water is actually full of good nutrients for the plants.
We strongly believe every green brownstone renovation should have a gray water system installed and being local Brooklyn gray water system installers is a core focus of our business model. The benefits impact the house water bill but also the local waterways in terms of reduced pollution. Conserving water just makes sense, even in NY.