Message to Our Customers


Model # ZRO-4

Internet # 100203211

Store SKU # 449959

Zero-Waste Reverse Osmosis Water Filtration System

This item has been discontinued.
The Home Depot no longer carries this specific product.

$465.00 / each



Model # ZRO-4

Internet # 100203211

Store SKU # 449959

This water filtration system can help convert your reverse-osmosis system to a zero-waste system by returning unused water from your reverse-osmosis system back to the home's hot water supply. It offers several benefits, including water conservation and faster fill time. It also helps eliminate noise created by the air-gap faucet.

California residents: see  Proposition 65 information

  • Use under your sink with an existing reverse osmosis unit
  • Filtering system is a combination of carbon block, sediment, and a membrane
  • Push-to-connect fittings
  • Faucet, hardware and installation kit included

Info & Guides

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Fitting size (in.) 
Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Automatic shutoff 
Faucet Included 
Filter change indicator 
Filtration method 
Reverse Osmosis 
Fitting style 
Push to connect 
Hardware Included 
Installation kit included 
Maximum feed water pressure (psi) 
Maximum feed water temperature (F) 
Maximum filtered water flow (gallons per min.) 
Minimum feed water pressure (psi) 
Minimum feed water temperature (F) 
Number of stages 
Product Weight (lb.) 
31.15 lb 
Water Filtration System Type 
Under Sink 
Water Filtration Technology 
Warranty / Certifications
Certifications and Listings 
NSF Listed 
Manufacturer Warranty 
Watts (the "Company") warrants each product to be free from defects in material and workmanship under normal usage for a period of one year from the date of original shipment. 


Rated 3.7 out of 5 by 7 reviewers.
Rated 4.0 out of 5.0 by A good little system I bought this unit about a year ago (time for new filters). It has performed great. It was easy to install (the tubes are all color coded). The waste water hooks up to your hot water system. There is a small pump that runs when the water is being filtered. The pump is very quite. I have never had a problem with pressure or running out of water. (We use a lot of RO water in our humidifier.) No broken parts. No leaks. No complaints. April 24, 2013
Rated 5.0 out of 5.0 by Save lots of Water. Estimates, depending on the unit, run from three to six-gallons of waste water for every gallon produced in an RO. We have had this Zero-Waste system for five and a half years and let me tell you, compared to our Culligan unit that we had for ovr ten-years we are saving about between eight and ten-gallons of water a day. The only trouble we have had was because the contractor installed the pressure gauge on the co-op water meter and probably used the setting of the unit out of the box. The motor ran on and on and I was sure I would have to replace the motor before long. I finally got off my dead rear end and checked incoming pressure at the meter one day and it was only 50 PSI. I upped to it 65 PSI and everything was better, toilets flushed better, water softener was more efficient, as was the dishwasher and the RO pump ran and was done in a few minutes. With the price of water going up and with it becoming more scarce, this Zero-Waste RO is perfect. July 5, 2014
Rated 1.0 out of 5.0 by Worst of Watts Premier! Bought this to replace my 5 stage Watts Premier R/O. The old unit worked fine, but wasted a lot of water. I remodeled my kitchen, and in the process, thought I would replace my old R/O with a new one since it was quite old and needed new filters anyway. I was going to buy the same unit (even though it was slow like all R/O's but decided on the zero waste for enviromental purposes. Boy was I wrong! This unit has less water pressure and produces about 3 glasses worth of water at a time, then runs dry. I am now going to try a single Culligan (US-EZ-1)filter. I will try to update this. February 17, 2013
Rated 5.0 out of 5.0 by ALL. THE GOOD, NONE OF THE BAD I replaced an older 4 stage unit because of the water savings. It performs as advertized. It is important to be sure that requirements such as hot water pipe length and water pressure are met. Water that normally would be wasted is stored in the hot water supply pipe. The water in a hot water pipe usually goes down the drain while waiting for hot water at the tap or the cold water faucet would have been used used. If the supply is too short it won't hold enough RO waste and if water pressure is too high the pump may have to work too hard to push the waste up the pipe. This system easily fills my 2 gal. pitcher without fading to a drizzle like my old unit did and the water tastes as pure even though it has less filters. The pump turns on after about a cup of water. I can't hear it unless the cabinet door is open and the house is silent. I researched the unit on line but bought it at Home Depot because it was available locally. It has T-valve adapters that fit at the hot and cold faucet connections so you don't have to pierce any pipes. This is a big improvement over older systems that used self tapping valves that eventually leaked. I've had it for almost a year now and disagree with statements by some that you would be washing your hands in contaminated water (when the water gets warm it's from the water heater so the waste water is down the drain) or that the pump is noisy (my refrigerator is louder). This system is the answer to RO. October 9, 2014
Rated 5.0 out of 5.0 by Very nice RO system We bought this system three years ago and it runs great. We use it for cooking and drinking all day long and its pressure is very good and constant. The only down side is that I couldn't find replacement filters in the local stores not even in Home Depot where we purchased it. However, I was able to order the filters from the company's website for very reasonable price ($13 per set). January 4, 2014
Rated 5.0 out of 5.0 by love this system We are here only for 5 months a year and have had this system for two years and just starting our third year. We are just now replacing the filters as we only use it for 5 months each year. We have never had a problem with the system and would highly recommend it. We like the fact that we do not waste any water with this system thus saving on water. We have never run out of water and we do use quite a lot of water from the system. Makes good tasting ice cubes. November 7, 2013
Rated 1.0 out of 5.0 by Never worked, professionally installed! Have a friend who installed one which works well. Mine never worked even after two checks of setup and 2+ hrs on phone with Watts tech. Returned to Homedepot and got full refund. December 25, 2014
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