A Nifty New Invention - Reverse Osmosis Water Purification That Doesn't Waste Water!

A reverse osmosis system that doesn't waste water?

Traditionally reverse osmosis water purification systems waste a tremendous amount of water during the purification process, typically 3 to 15 gallons of waste water for every gallon of clean water produced. This new system doesn't waste any.

Obviously this is not very good for water conservation. But Watts has invented a way of recycling the contaminated waste water, eliminating the water normally wasted. They just pump it into the water heater.

Watts Premier Zero Waste ZRO-4 Reverse Osmosis System

The Watts website claims their patented ZRO-4 Reverse Osmosis System is the first ever that does not waste water. Instead of running the contaminated waste water down the drain like other RO systems, the zero waste system pumps the contaminated water into the water heater. Typically one doesn't drink hot water, and bathing washing and cleaning with it should be fine.

The instruction manual states that the ZRO-4 RO system needs to be located at least 25 feet from the water heater. I wonder why. What would happen if the RO system is closer to the water heater than 25 feet? If anyone knows why this is a requirement please let me know! What about tankless water heaters?

To me this is a brilliant idea for an invention. It's simple, inexpensive and saves a ton of water. Probably has a very solid patent that would be difficult to get around, although I haven't really studied the patents. They are easy enough to find on Google's patent search.

The level of contamination of the waste water isn't very high, and should not pose a problem unless you regularly consume hot water, something that is fairly easy to avoid.

The Watts ZRO-4 reverse osmosis system reduces Arsenic (V), Cysts, Cyrptosporidium, Giardia, Entamoeba and/or Toxoplasm, Barium, Hexavalent, Chromium, Trivalent Chromium, Copper, Lead, Fluoride, Cadmium, Radium 226/228, Selenium, TDS, and Turbidity. It also has filters since RO systems can't get every nasty out of the water.

There are some potential problems with operating the system with hot water demand systems and some hot water recirculating systems. Since the RO system connects to both the hot and cold water lines, any other equipment that also connects to both the hot and cold water lines present opportunities for problems.

Hot water circulating and hot water demand systems that pump water from the water heater to purge the cooled off hot water in the pipes, or that circulate warm water for instant hot water purposes can cause water to flow through the RO unit just as though the RO pump is running.

The flow of water though the RO system resulting from the operation of the recirc pump may increase the delivery time for hot water to reach the fixtures. With the warm water circulating systems and with the hot water demand type systems the cold water piping can end up full of contaminated waste water.

Watts also has a retrofit version of it's zero waste system which allows you to convert your existing system to a no waste system. The retro-fit system includes a solenoid valve in series with the pump used for pumping the contaminated water into the water heater.

I don't know if a demand pump would cause water to flow through the solenoid valve backwards or not because I haven't had an opportunity to test one, but it might be a viable solution for using both the ZRO-4 and a hot water circulating or demand system...but someone needs to test it to be sure.