#1 Home Improvement Retailer

Internet # 100203211

Model # ZRO-4

Store SKU # 449959

Zero-Waste Under Sink Reverse Osmosis Water Filtration System

Apply Now
Pay $336.43 after $50 OFF your total qualifying purchase upon opening a new card. info
Apply for a Home Depot Consumer Card
  • Four-stage filtration system removes impurities from the water
  • Utilizes a reverse osmosis system to minimize waste
  • Not designed for use with tankless water systems
  • View More Details
0 in stock
Free & Easy Returns In Store or Online
Return this item within 90 days of purchase. Read Return Policy

Product Details

Remove impurities from your water with the ZeroWaste (R) 4 stage reverse osmosis system. This four-stage filtration system uses the same process as many major bottled water companies to reduce salts and other impurities from water for a high quality, clear and great tasting result. It also conserves water and increases membrane production for a faster fill of the storage tank. There is also no need for an air-gap faucet that causes unwanted noise.
  • Includes RO Pure Plus Reverse Osmosis Module with pre-installed filters, 3 gal storage tank and faucet with parts
  • Check valves installed in the filter lid between cartridges prevent back-flow
  • Shut off valves in each filter head shuts off the water flow when cartridges are removed
  • Four stages of filtration trap sediment and other particles to provide clean drinking water
  • Fits under your sink with minimal space requirements
  • Easy filter changes
  • UPC, IPC and IGC 159-2000a
  • Return Policy
  • California residents


Dimensions: H 17.0 in, W 16.5 in, D 5.5 in


Fitting size (in.)0.25 inProduct Depth (in.)5.5 in
Product Height (in.)17.0 inProduct Width (in.)16.5 in


Application TypeWater TreatmentBacteria Reduction (%)99.99
Chlorine reduction (%)98.4Color/FinishWhite
Contaminants FilteredLead, Chlorine, Bacteria, Copper, FluorideCopper Reduction (%)99
Ease of InstallEasy InstallFeaturesAutomatic shutoff
Filtration MethodCarbon Block, GAC, SandFitting stylePush to connect
Fluoride Reduction (%)93.9House Hold Size5-6 people
IncludesFilter, Hardware, Installation kitIndoor/OutdoorIndoor
Iron Reduction (%)0Lead reduction (%)98.6
Maximum feed water pressure (psi)85Maximum feed water temperature (F)100
Maximum filtered water flow (gallons per min.)0.5Minimum feed water pressure (psi)40
Minimum feed water temperature (F)40Number of filters included4
Number of Stages4 StagePack Size1
Product Weight (lb.)26.85 lbReplacement Filter TypeReverse Osmosis Replacement Filters
Returnable90-DayWater Filtration System TypeReverse Osmosis
Water Treatment TypeReverse Osmosis Filter Replacements

Warranty / Certifications

Certifications and ListingsIAPMO CertifiedManufacturer Warranty1 year

Questions & Answers

Q:Does it affect the water heater in any way?
by|Apr 11, 2021
1 Answer
Answer This Question

A:  Hi Anil, As long as the unit is 25ft or more from the heater you should not notice warm water at the RO unit. There will be a higher concentration of dissolved minerals in the water going back to the heater but with the typical 40-50 gallon water heater the dilution when in the tank should not be noticeable. Thank you

by|Jun 15, 2021
    Q:Can discharge be hooked to side arm?
    by|May 9, 2020
    0 Answer
    Answer This Question
    Q:What is the maximum distance, in feet, allowed between the tank and the RO faucet? I'd like to i...
    by|May 6, 2020
    1 Answer
    Answer This Question

    A:  Pat, thanks for reaching out! The unit comes with 4 ft of tubing between the unit and the tank and 4 ft of tubing between the unit and the faucet if you add more tubing you will reduce flow going to the faucet and risk the unit not being able to regulate pressure and shut down properly.

    by|Jul 22, 2020
      Q:Says "Does not work with tankless water heaters." Does that include having a regular gas water h...
      by|Mar 12, 2020
      2 Answers
      Answer This Question

      A:  The limitation with this system is .5 gallons per minute into the 3 gallon storage tank. You would not want this system to feed any hot water supply basically, unless you added a much larger storage tank.

      by|Mar 25, 2020

        A:  Hi, Correct, this includes point of use temperature boosters, we would not recommend using this product with them. Best, Watts team

        by|Mar 13, 2020
          1 found this answer helpful
          Showing 1-4 of 44

          Customer Reviews

          4.3 out of 5
          • 4.3
            out of 21 reviews
          • 79% recommend this product
          Filter by:
          Showing 1-10 of 21 reviews
          Good idea. Low operating costs. Some trade-offs.
          I've had mine for 4 years, and it has been good, but not perfect. The Good: 1. The filtered water tastes wonderful! I think about that every time I fill my glass. It's not about knowing that all the garbage in my municipal water supply is being filtered out. It's the taste. 2. I like the zero waste feature, but it has trade-offs as listed below. 3. The replacement filters are relatively inexpensive, compared to many. 4. I bought a water tester, and I have tested my water enough to know that I don't have to replace the filters on schedule. With my family of 5, I do the 6-month filter change once a year. I haven't tried to go longer. 5. The motor is reasonably quiet. Mine doesn't have a cushioned motor mount like the picture here shows, so I added a cushion. 6. No need for an air gap on the waste line. The Bad: 1. The ceramic faucet valve that it came with was leaking in just over a year. There's a different faucet in the picture here. 2. While you don't waste water, you will waste energy. This unit pushes the "brine" into the hot water pipe under your sink. This pushes it back through the hot water pipes to the water heater, and in turn, hot water from the bottom of the tank is pushed back out of the tank into the cold water system, where it cools. The energy used to heat that water either goes to heat your house, it goes to waste, or it adds to the cooling load on your A/C system. I have no idea how the total energy loss compares from this system to.a wasteful one, but it's a trade off. 3. As a result of the brine in the hot water pipes, when I wash my hands in a nearby bathroom, I frequently feel the hot water go cold (brine) before warming up again. Others have complained about the fittings. I soldered copper and brass valves to my hot and cold water supplies because I'm that kind of guy. I'm not a fan of push-in connectors, but I've used the rest of the supplied connectors without any problems. 4. Buy a filter wrench. What's moderately hand tight when you put it together gets a lot tighter 6-12 months later. For the premium price, it should be included. Summary: If I were to start over, I would install this by my hot water system, run the return brine backward through my hot water pre-heater tank (instead of my water heater tank), and put only the expansion tank and finish filter under my sink. It would solve the 2nd and 3rd problems I described above. Actually, I'm installing another one at a second house and doing just that.
            • Recommended
            10 found this review helpful
            Highly recommended
            It is a replacement of exact same system that lasted 12+ years of daily use. Very much appreciate “zero waste”. This review is based on our previous system, as the new one had only been installed about a month ago. The original system required professional installation (electric outlet was needed and plumbing fittings had to be installed) but the replacement was hooked up to old fittings by us (not really handy people).
            • Verified Purchase
            • Recommended
            Got about 10 years ago, made my cold water hot and my hot water cold
            The theory is to pump the waste water into the hot water tank. Maybe its different now but that's what it was like a decade ago when I put the Watts unit it. The waste water goes into the hot water line, that pushes the hot water back into the hot water tank along with cold waste water. So turn on the hot water facet and you get cold water as the hot water was replaced with cold in the line. This was a 20 year old hot water tank in a 4,000 sq foot house with lots of pipe. We have a well and water pump. Not sure if that makes a difference but then the cold water started coming out warm. I theorized that the cold waste water pumped into the hot water tank displaced hot water in the tank and forced that hot water to go somewhere. My guess is it went to the cold water lines. I routed the waste water back out into the sewer lines and now everything works fine again. Just not saving any waste water. System has lasted a long time and seems good, just didn't save on waste water.
              Water filtration unit
              I bought this unit at least 8 years ago, don't remember where I bought, or how hard it was to install, but what I will give a review it makes my well water taste great. Why I am writing this review is I am stuck at home because of the Covid so why not change my filters on my RO water filtration system. I did not change my filters regularly but the water still tastes great. I think I only changed them once after 4 years but will try to be more responsible and follow the manufactures recommendation of at least once a year and the membrane every 5 years. I do send my water in for testing at the health unit once a year and so far everything comes back good. I live on an acreage with well water and it has no iron but it has a sodium taste to the water. It is hard to stomach so I tried this RO System and I can say it works great 8 years later. We only use about 2-4 gallons of water a day so it easily keeps up and I had it hooked to my fridge only. I recently hooked it to my Culligan water cooler and it also works great. I don't give many reviews because most people give a review the month they buy the product and I find that unbelievable but I bought this unit so long ago and I had no problems with it I give it a 5 thumbs up.
                • Recommended
                1 found this review helpful
                I'm very excited that I am not wasting water. ...
                I'm very excited that I am not wasting water. The pump only goes on occasionally and is not very loud. However, I thought the price was very high compared to the regular filters.
                • Verified Purchase
                We have had an RO system for the last 30 years. We remolded our kitchen & decided to get a new on...
                We have had an RO system for the last 30 years. We remolded our kitchen & decided to get a new one. I am so happy that I researched the ones available & chose this one. More pressure, always enough even for a party function with no waste
                • Verified Purchase
                • Recommended
                1 found this review helpful
                I have had this for 15 years now. The water it produces is amazing. Over time this is what I have...
                I have had this for 15 years now. The water it produces is amazing. Over time this is what I have liked about it most. - it is a Watts product, a huge plumbing & water treatment company. They are not going out of biz. -Watts Tech support, fully informed experts to help you out when needed, if the pump stops working etc. -Watts STILL makes parts for this thing, eventually the pump will burn out, or the transformer, or the big tank bladder will burst and need replacement etc. Can still get those parts, and they are an easy DYI install. - The design is virtually the same all these years later, which means they hit the mark, and you won't have to worry about next years model being better. The filters and pump are linear in design, not a blocky or square thing like some of the others. So it fits along the side wall under my sink and does not (except for the tank - fact of RO life) take up "too" much space. It is a zero waste, which means the waste water produced by every RO system, goes back down the hot water line and into your Water Heater tank. I live in LV, NV, and we are in a drought. So any water "wasted" is a sin. My water bill is almost nothing, but I'm sure if I was tossing 4-12 gal of waste per 1 gal recovered, my water bill would be out the door. Yes, it's pricey, but in the end it was so worth the money. In savings on my water bill, and especially NOT having to buy bottled water. You know, that stale bacterial "filtered from a municipal source," throw the plastic bottle away water, go to the store and get it water - you are better off without. And finally, the best benefit any RO system is that not only are you more inclined to drink water - for good health, but since it is limitless, you can use it of cooking. So your spaghetti, your rice, your whatever is made with clean fresh uncontaminated water. Lets face it, no one dumps four bottles of bottled water in a pot to boil spaghetti. I did the math, base on the amount of water my family of four consumes and uses for cooking, if we went out and bought bottled water for the same usage, we would spend $1200.00-1500.00 per year. No kidding. With this, two sets of the hanging down filters, plus one RO filter per year, $100.00 bucks. Saving literally over a thousand bucks per year. Side note- they say the RO filter only needs to be changed every two years, but I change it annually, it gets a little slimy in that RO canister, if you let it go the full two years. A time tested, completely repairable, backed with by a solid company with great tech support. Buy it.
                  • Recommended
                  1 found this review helpful
                  The ZeroWaste Reverse Osmosis system works GREAT Nice fresh clean water Thank You
                  • Verified Purchase
                  • Recommended
                  Our installer really liked it and he is letting his boss know how easy it was to install.
                  Our installer really liked it and he is letting his boss know how easy it was to install.
                  • Verified Purchase
                  • Recommended
                  3 found this review helpful
                  Great system
                  This system works great. Fairly easy to install. However, for my install I needed to replace a few fittings because I did not use the supplied faucet as I had a fairly new airgap faucet already that mached my other faucet.
                    • Recommended
                    2 found this review helpful
                    Showing 1-10 of 21 reviews

                    Compare Similar Items

                    current product

                    Contaminants Filtered

                    Lead, Chlorine, Bacteria, Copper, Fluoride

                    Lead, Chlorine, Bacteria, Copper, Fluoride, Iron

                    Lead, Chlorine, Bacteria, Copper, Fluoride, Iron

                    Lead, Chlorine, Copper, Fluoride

                    House Hold Size

                    5-6 people

                    3-4 people

                    3-4 people

                    8+ people

                    Number of Stages

                    4 Stage

                    6 Stage

                    5 Stage

                    7 Stage

                    Filtration Method

                    Carbon Block, GAC, Sand

                    Alkaline or Calcite, Carbon Block, Coconut Shell Carbon, Sand

                    Carbon Block, Coconut Shell Carbon, Sediment

                    Alkaline or Calcite, Coconut Shell Carbon, GAC, Remineralizer, Sediment, Thin Film Composite Membrane

                    Number of filters included