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Free shipping on most orders over $199 in the continental USA. $299 minimum for extended delivery states: AK, AL, AZ, CA, HI, ID, MD, ME, MN, MS, MT, NH, NV, OR, UT, VA, VT, WA, WV. Freight orders excluded. Speak to a water expert for more details.
Our Master Water Specialists and Certified Water Specialists review your water analysis and address your specific water problems. WE then design a system that we'll guarantee will solve your water problem(s) and back it with our One-Year Money Back Promise (Guarantee).
It all starts with a Laboratory Test of your water. Then, our Master Water Specialists and Certified Water Specialists will review the results of your water analysis and scientifically discuss the best way to treat your water, provide on estimate of how to do that, and then we provide you a One-Year Guarantee of Satisfaction. It's our Promise to You that our system will do what we say or we will give you your money back*
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Reverse osmosis is used in aerospace, biotech, and high-tech manufacturing. The Defender brings that same level of protection to your entire home by reducing TDS by up to 99% and removing thousands of harmful impurities.
Everything that doesn’t belong—gone at 0.0001 microns
Precision-built in America with better parts, better oversight, and better support
High-efficiency RO with built-in recycle and blending functionality
Long-life membranes, stainless steel, and smart design. Built for the long haul
The Defender system can drastically reduce chemicals, bacteria, and heavy metals throughout your home. You’ll have peace of mind knowing your water is cleaner and safer from every tap.
Your water will taste fresh and pure, free from unpleasant odors and flavors. Enjoy better-tasting coffee, tea, and meals without needing bottled water.
This system reduces wear on your pipes and appliances caused by hard water and contaminants, saving you money on repairs and extending the life of your home’s infrastructure.
Ideal for private wells, this system offers multi-layered protection against sediment, chemicals, and pathogens, ensuring safe, usable water throughout your home.
Skip the cost, waste, and hassle. Defender delivers better-than-bottled quality from every faucet—eliminating the need for single-use plastics or countertop filters.
RO water prevents mineral buildup in fabrics, so clothes and linens stay brighter, softer, and free from musty odors.
With pre-treatment options, ultraviolet disinfection, storage, and water delivery, this product is customizable to meet your unique water quality needs.
Every detail of a Defender Whole-House Reverse Osmosis System is built with longevity and reliability in mind. Superior components and quality control add up to a system that you can rely on.
We use stainless steel reinforced fittings, a multi-stage stainless steel booster pump, and the highest quality stainless steel valves to make sure you always have clean, high-quality water.
| Product Features | Defender Whole House RO | The Other Guys |
|---|---|---|
| Pump | Multi-Stage Stainless Steel Booster | Cast-Iron Rotary Vane |
| High-Pressure Fittings | Stainless Steel Reinforced PVC | PVC |
| Valves | Stainless Steel | PVC/Brass |
| Warranty | 2-Year "Bumper-to-Bumper" | 1 Year Limited |
| Tech Support | Lifetime Expert Tech Support | Outsources Limited Tech Support |
A reverse osmosis system can clean up a mud puddle. However, the question becomes... for how long? With proper pre-treatment, a reverse osmosis system will give you years of reliable performance and outstanding water quality.
No two wells produce the same water. The chemistry can vary dramatically—from iron, manganese, and sulfur to bacteria, nitrates, and PFAS. That’s why US Water Systems follows the principle: measure twice, cut once. Before recommending a Defender™ system—or any solution—we strongly advise starting with a laboratory-grade water analysis. It’s the most responsible first step toward solving water quality issues the right way.
The cost of the Waterlogix™ test kit is fully credited toward any recommended system purchase. That means your lab-grade water analysis is essentially free when you’re ready to move forward—ensuring our solution is right the first time and allowing us to stand behind its performance with confidence.
Water from a municipal source has 3 primary and predictable waterborne contaminants that would be addressed prior to entering your RO system. These contaminants are sediment, chemicals such as chlorine, and limescale.
Permeate 
Pre-treated water is pumped into the RO membrane at about 150 PSI
As the water moves through the wound passages in the membrane, it’s separated into two streams: Permeate = Good Water Concentrate = Waste Water
The treated water (Permeate) then flows out of the membrane through the collection tube and into the storage tank
A portion of the wastewater (Concentrate) can be recycled back to the input to improve recovery, and the small portion remaining flows harmlessly down the drain
| Contaminant | Reduction | Contaminant | Reduction |
|---|---|---|---|
| Algae | 99.99% | Mercury | 98.00% |
| Aluminium | 98.00% | Mold | 99.99% |
| Amoebic Cyst | 99.99% | Nickel | 95.00% |
| Arsenic | 95.00% | Nitrate | 89.00% |
| Asbestos | 99.00% | Phosphate | 95.00% |
| Atrazine | 95.00% | Pottasium | 95.00% |
| Bacteria | 95.00% | Protozoa | 95.00% |
| Algae | 99.99% | Mercury | 98.00% |
| Aluminium | 98.00% | Mold | 99.99% |
| Amoebic Cyst | 99.99% | Nickel | 95.00% |
| Arsenic | 95.00% | Nitrate | 89.00% |
| Asbestos | 99.00% | Phosphate | 95.00% |
| Atrazine | 95.00% | Zinc | 97.00% |
| Bacteria | 95.00% | Z, 4-D | 95.00% |
City Water: Hardness treatment, chemical removal, and sediment filtration must be used for pre-treatment.
Well Water: Requires laboratory water testing and analysis for recommendation with a performance guarantee. This is the only way to ensure proper system performance.
The typical system requires a minimum volume and pressure to for nominal and efficient operation of at least 10 Gallons Per Minute @ 40 PSI. Give us a call to find out how to test this.
Two (2) 1/2" air-gapped drain connections capable of handling at least 3 Gallons Per Minute. This can be a riser drain or a floor drain.
You will require one (1) 220v connection on a 20A circuit. You will also require two (2) 110V connections on a 20 A circuit. Please contact a certified electrician to confirm your application supports this.
The minimum requirement for door openings is 29" wide. It is recommended to ensure you have a open area at least 72" width and 30" depth with access to front and sides.
RO water can be aggressive to soft metals like brass and copper, while plastic plumbing materials are unaffected. If you have soft metal plumbing, pH adjustment is usually required to protect the infrastructure and balance the alkalinity.
Still Have Questions?
Overall rating: 4.818182 / 5 from 33 reviews.
The Defender Whole House Reverse Osmosis System offers industrial-grade water purification, reducing TDS by up to 99% and removing harmful impurities. Customers appreciate its easy installation, high-quality components, and the significant improvement in water taste and quality. This system is ideal for both municipal and well water, providing long-lasting, reliable performance.
Review topics: ["support","customer service","service","system","staff","quality","results","water","instructions","installation","issues","decision","call","components","salt","works","package","flushing","guys","tank","choice","tds"].
"I’m very pleased and impressed with this RO system took my total TDS of 1760 down to 22. Customer service was very helpful and friendly to talk with. Thank you US Water!"
— Scott, B. (4/5)
"I replaced the Grunfos system with this system. It is not cheap, but the water quality is 1000% better than the previous system. The first thing I noticed was taste, better than bottled water. I have the house cleaned every two weeks and the toilets would get a black slime build up in the bowl and now they are spotless. I have an irrigation system for the lawn and garden and water recovery is instantaneous. The system I replaced would use 2/3 of 150 gallon tank and would take 4 hours to refill. More ideal construction and all filters, pumps and connections located in one system other than a tank attached separately that supplies a chemical agent to keep the reverse osmosis filters from buildup. Well water is located on a peninsula surrounded by Leadenwah creek and marsh. Salt content in the well water is high, but clear. No salty taste in the treated water after it’s processed. The well water is diverted to a salt water pool and it’s clean with weekly pool service."
— Bruce I. (5/5)
"Wow was I lucky to find US water. My water was not the best and was testing with a lot of arseni, iron, magnesium, and a few other things. I had water treatment installers telling me my water was so bad that I should go with a bigger company and other bigger companies giving me quotes of $40,000 for a whole home system which in my mind was outrageous. That’s when I found US water system and began the process of finding out what my best solution was. From the moment I sent them over my test results they were able to build me a whole home treatment system based on my water quality and for less than half the amount I was getting quotes for. Shipping was fantastic. I got an email notice stating that it was going out and received it within four days delivered to my door by a shipping company. When the components arrived at first, I was a little overwhelmed by all the boxes, but after opening them all up and contacting their Help support line, I was able to decipher everything in detail how things worked. The customer service and their technical support that US water system supplies was amazing is all I can say anytime I had a question I picked up the phone and there was always someone there to answer it within minutes. There was no waiting on hold for 20 minutes or 30 minutes. It was like they were there just for me. I did hire a plumber because I wanted it to look nice and neat, but this is definitely a system for a homeowner with some handyman experience would be able to install. We are finally up and running and the water is so clean and safe to drink. It’s amazing how this system works. We were getting all kinds of spots on our dishes from the buildup of the heavy metals and now it’s just sparkling like a diamond ring, even after install and getting everything up and running, I am still able to give them a call and they still are more than happy to assist me when it comes to dialing the pH in and all the products that are required from my system. Oh, and did I mention that the helpline is also open on Saturdays and holiday weekends. Amazing Company !!!!"
— Wanis, I. (5/5)
"I have had my defender 4000 US Water Systems RO system in place now for just over one year. I had it professionally installed by a water specialist because I was not in the area when the project needed to be completed. However, after reviewing the project and the explicit instructions provided by US Water Systems I decided that it was definitely a DIY project that I could’ve handled myself. I have since called the technical support line a couple of times simply to see what I might do to keep my system, running smoothly and answer a few questions regarding water quality, and such, both times I called technical support. I spoke with John Shepard he was extremely helpful and easy to talk with. I would highly recommend the system to anyone looking to have quality water throughout their entire home."
— Brian A. (5/5)
"After getting a detailed water test by a lab I received levels that were not fit to consume. My water tested out above 3000 ppm TDS, extremely high in Sulfates. The inside of my dishwasher looked like it was painted white. After installing a Defender Whole House RO 4000 filter, my TDS dropped to 9 ppm. I have been running it for 1 1/2 years and my TDS number is still 10 ppm. The dishwasher looked brand new after a few washes. way beyond any expectation I had. Great customer service too. Thank you !!"
— Jeff D. (5/5)
"Beat my expectations, really. Reduced TDS from 500 to 15 on city water in San Diego."
— Ryne O. (5/5)
"The staff was great every time I called with questions. And the system is great. I’m only sad that I waitied this long to install a reverse osmosis whole house system."
— Jay C. (5/5)
"This RO system rocks. Only thing better than the system was dealing with the company. From sales to tech support I would rank 10/10! Thanks US Water Systems! You guys and senoritas are 24k all day. Keep it up folks!"
— Troy K. (5/5)
"I purchased the Defender 4000 gpd RO system with anti-scalant injector and a Flexx Infusion filter with H2O2 injection. The installation was relatively easy, but the tech support (John) was super. I read the manuals and watched the videos, but the tech support was very useful and confidence building. Over a few days we must have spoke 8 times and John was always quick to return my calls and was very knowledgeable. After about 1 week of operation I am still tuning in settings . . . H2O2 levels, recycle level and Perm. vs Conc. levels. I am now at 2 gpm conc. , 2 gpm perm. and 1 gpm recycle. Raw well water is >2,500 TDS with lots of calcium and iron bacteria, but after filtering and RO processing we are getting <30 ppm TDS. Minor Issues . . . 1) some minor differences between the manual or the installation video, but tech support resolved. 2) water pressure into the house . . . the grundfos booster pump spikes over 70 psi and also oscillates every ~10 seconds (low pressure/high pressure). I need to follow up on this last issue Some unique details I added (see photos). A drawer to store manuals and spare parts, wheels on the shipping pallet so I can easily move to service and a tap mid-way up the storage tank to draw clean water via gravity down to a separate application outside the house."
— Donald H. (5/5)
"Best"
— Sukhi D. (5/5)
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