Reverse Osmosis Water Filtration Systems

By American Plumber

Pentair (American Plumber) is a leader in the water filtration industry. They offer a full line of water filter housings, replacement cartridges and accessories, as well as the quality Reverse Osmosis unit offered on this page.® is pleased to offer their extensive line.

Reverse Osmosis WO-2550 Multi-Stage Filter System

American Plumber - WRO-2550
RO-2550 Reverse Osmosis features:
  • Now you can have cleaner, fresher tasting water at your fingertips
  • Reduces bad taste, odors, salts, and dissolved solids such as lead, copper, and chromium, as well as other unwanted heavy metals and mineral elements
  • Produces up to 15 gallons of high quality water per day
  • Excellent water treatment choice for persons requiring low sodium diets
  • Chrome dispenser faucet included
  • One of the best filtration systems available; reduces particles as small as 1/1000 of a micron by mechanical means
  • Use with chlorinated or non-chlorinated incoming water supply
  • Neatly installs under the sink
  • Filtered water is stored in 2.8 gallon storage tank for immediate dispensing
  • Rejected contaminants are forced down the drain
  • NSF and ANSI Standard 58 certified to reduce Cryptosporidium and Giardia cysts by mechanical means
  • Water pressure inlet range: 40 to 100 psi
  • Operating temperature range: 40° to 100° F.
RO-2550 R.O. Drinking Water System = $220.13
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The WRO-2550 Reverse Osmosis System can help reduce the following contaminants:
  • Barium
  • Chromium (Hexavalent)
  • Chromium (Trivalent)
  • Copper
  • Cysts
  • Cryptosporidium
  • Giardia
  • Lead
  • Radium 226/228
  • Selenium
  • Sodium Chloride
  • TDS (Total Dissolved Solids)
Please note: Contaminants or other substances reduced by this water treatment system are not necessarily in your water. Only a test of your water can determine if any are present.

Replacement Membranes & Cartridge Sets:

Model Description Price & Quantity
WROM-50T Replacement membrane for WRO-2550 (3rd stage) Discontinued
WRO45R Pre-filter kit - 1st stage sediment; 2nd stage carbon block Discontinued
(old #WIC)
4th Stage GAC Post Filter - 1/2 micron - 1/4" FIPT - 2" x 10" $12.90 Enter a quantity and
American Plumber Replacement Membranes & Cartridges for Discontinued Models
WROM-230TN Replacement membrane for discontinued WRO-3500 $128.54 Enter a quantity and
WROR Cartridge set for discontinued WRO-3000 & WRO-3500 $61.98 Enter a quantity and

Sani-System RO Unit Sanitizer

Great reasons to use RO sanitizer:
  • Sanitizes the reverse osmosis system in only 60 seconds time
  • Will not leave an after-taste or smell when used as directed
  • Chlorine-free and non-corrosive
  • EPA and NSF Certified for a 99.99% kill rate
  • Easy to use single-dose packets
Get the job done fast with these conveniently easy-to-use, pre-measured sanitizing packets. When used as directed, Sani-System kills bacteria such as Staphylococcus aureus (Staph), Escherichia coli (E. coli) Listeria as well as many other micro-organisms that grow on the untreated surfaces of water quality equipment. This sanitizer eliminates odors while sanitizing tanks, lines and hoses. These sanitizers are a great way to help your system remain free and clear of bacteria growth, which in turn helps your mind stay free and clear of worrying about your water quality.
Reverse Osmosis Sanitizer Packet - 0.25 FL. OZ. = $4.77
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Order 24 or more for Great Savings - Order 96 or more for Even Greater Savings!
Pricing discounts will show up in your shopping cart.

Directions for Sanitizing:
Step 1: Shut off water supply to RO unit and remove membrane and all filters. Use rubber gloves and store filters and membranes in water to prevent damage.
Step 2: Open filter water faucet and depressurize system.
Step 3: Pour entire packet of Sani-System directly into the first main housing unit. Make sure filter water faucet is closed and turn on water supply.
Step 4: Allow system to fill with water. The time will vary depending on the water pressure. However, the system should be full within 5 to 10 minutes without the filters or membrane. Flush the system two times.
Step 5: Replace or re-install membranes and all filters

Related Items & Accessories

Frequently Asked Questions

Q. "What is Reverse Osmosis?"
A. Reverse Osmosis is a process in which water is forced by pressure (at least 35psi) through a semi-permeable membrane. The good water passes ("squeezes") through a special membrane while the dissolved and particulate materials are sent down the drain.

Q. "What does Reverse Osmosis remove from the water?"
A. An RO system is used typically to remove dissolved solids such as salts and minerals (lead/mercury) out of the water (up to 2000 ppm).

Q. "What doesn't Reverse Osmosis remove?"
A. Most ROs are not capable of taking nitrates out at sufficient EPA recommended levels. RO will not remove chemicals or bacteria. The RO membrane itself will not remove chlorine. A few of our units (as well as some others) have a carbon pre-filter which will. Many types of bacteria have to be killed before going into an (any brand) RO. Some bacteria have the ability to grow through the RO membrane. Once on the other side of the membrane, the bacteria can start new colonies.
Also, if your water has a bad taste to it you probably need a carbon filter. We offer a number of great carbon filters.

Q. "How often should I replace my filters and membrane?"
A. This is a very common, (and difficult to answer), question. It depends a lot on your water conditions, water quality and your usage. We believe that in no case (no matter what brand that you have) should you keep the pre and post filters longer than a year (changing them every six months is better) nor the actual RO membranes longer than two years (changing once per year is better of course). To see what RO filters and membranes replacements that we offer view me. As you can see, we offer replacements for all of the RO models that we have ever sold. The manufacturer (not us) states that the recommended filter change for chlorinated water: Pre-Filter = 2 months; Post-Filter = 6 months; Membrane = 2 years. They state that for non-chlorinated water: Pre-Filter = 6 months; Post-Filter = 6 months; Membrane = 2 years.

Q. "I have excessive nitrates in my water. What do you recommend?"
A. We suggest a distiller (we do not sell distillers).

Q. "What if my hardness is greater than 10 grains per gallon?"
A. If your water is harder than 10 grains per gallon, then it will tend to foul the RO filter prematurely and will void any warranty. This is the case with almost all brands of RO systems. If your water is that hard we would recommend a water softener.

Q. "I have an RO system and there is water coming out from underneath the water dispenser faucet. What is wrong?"
A. More than likely you have an air gap style faucet. This is a safety feature. If there is any kind of clog or kink in the RO drain line, water will come out from under this style of faucet.

Q. "What is the difference between the TFC and TFM membranes?"
A. Basically they are the same membranes. TFC and TFM are both abbreviations for 'thin film composition' membranes.

Q. "Do you carry parts for RO systems?"
A. Absolutely, for the brands that we sell and have sold. Just click here...

Q. "My pH is 3.0, my hardness is 43 grains, etc ... Can you tell me what I need?"
A. We sell top quality products for many water needs, however due to liability reasons, we will not recommend which system you need. Please note that the systems that we sell are very good at solving specific water problems. We can't say if it will solve your problem. If you know what you need we can sell it to you at a great price.

Q. "I've seen RO that cost less than the ones you offer?"
A. Yes, we could offer cheaper priced systems as well. If you have spent any length of time looking at our extremely large catalog we know that you have seen how low our prices are. When deciding what RO to offer we decided that lowest priced models aren't necessarily a bargain in the long run. Reverse osmosis systems need new membranes and filters on a regular basis for example. Make sure to compare those prices and ratings as well. Our customer satisfaction rate is very important to us. It is our hope, that word of mouth and repeat business (we have sold many RO due to word of mouth) will keep us on top. We think you will agree that buying a "cheapy" unit isn't necessarily a bargain in the long run.

Q. "My RO continues to run. What is wrong?"
A. Check the storage tank; it might not have enough air in it. The tank should have between 5-10 lbs of air in it when empty. Too much air will cause an RO to shut off prematurely.

Q. "We have been considering buying a large 'whole house' RO system. Would the largest RO units that you offer work for our main water line. ?"
A. Our largest RO really isn't big enough (nor designed) for a whole house application. We do offer a very nice whole house water filtration system but it isn't an RO system.

Q. "What kind of warranties do the above reverse osmosis systems have?"
A. All have at least a one-year warranty on the components. The manufacturer will replace any defect arising in any of the parts within one year from the date of purchase. Labor for installation is not covered and there is no liability assumed by any of the companies for damage due to water leakage. This is the "standard" in the industry.

Q. "Will an RO produce 'pure' water"?"
A. Many use the word "pure" and many books have been written on the subject. Purified water is a term that has little meaning unless additional specifications are supplied such as; salt free, bacteria free, etc. Distilled water is probably as close to "pure" as water can get. It is made by evaporation and removal of all solid particles plus dissolved material. Purified water by the reverse osmosis method probably means that the original water has reduced mineral content. Purified water by ultraviolet light probably means that the water source was passed through an ultraviolet system in hopes of disinfecting the water. It is generally recognized that no single water treatment method is a catchall for all possible contaminants. Each water treatment method has its strengths and weaknesses and all are dependent on the condition of the water source.

Q. "I've heard that I shouldn't use copper pipes with any/all brand/s of RO system/s?"
A. Most brands of RO system will reduce at least 85-90% of salts in water, so you can assume the water salts concentration would be about 1/9th of the content in the feed water. The aggressiveness of this purified water towards the materials into which it comes in contact is a function of its purity. The better the purity, the more its aggressiveness. Piping after an RO unit should therefore always be non-metallic. RO units will pass all the CO2 that is in the feed water. This means the water will be more corrosive. Don't use copper piping after any (brand of) RO system.

Q. "I just installed a new filter cartridge and my water is cloudy/white?"
A. After you install a new filter (this is the case with any/all brands of filter cartridges) you should run it for a few minutes. Generally cloudy or white water indicates air in the line and this is natural and normal with the replacement of a cartridge. Air will enter in the housing, lines and cartridge. Just run the water for a few minutes and the cloudy conditions will go away (unless you have VERY cold water in which case it is the oxygen in the water that could be making the water look cloudy). It is always a good idea to run the water free-flowing for a few minutes after installing any brand or type of new filter cartridge.

Q. "Is it true that ROs waste a lot of water?"
A. ALL brands of ROs "waste" some water. With some systems it takes as much as 10 gallons of water to produce one gallon. Our systems are much better than that, but please understand, no matter what brand, there will be quite a bit of "waste" water that is used with an (all brands) RO system.

Q. "My RO is almost new and is rated to 'produce' 24 gallons per day but it only produces about 6 gallons per day if I'm lucky?"
A. Hopefully you purchased it from us :-). Seriously though, ratings by (honest) manufacturers are based on "ideal" situations. Please note, for example, both the pressure inlet and the temperature of the source water affect the production a lot (as well as the quality of the source water as well as the back pressure from the RO bladder tank, etc.). The lower the pressure inlet, and/or the lower the inlet temperature, and/or the worse the quality of the source water = the less the amount of water that is produced by your RO system. A "typical" 24-gallon per day rated RO could take over 12 hours to fill the 2-gallon storage bladder tank. Is this crazy or what? It just doesn't seem right that with a 24 gpd rated RO (just an example, it could be a 30 gpd RO) that it takes as much as 12-16 hours to fill a two-gallon bladder tank. Yes, we agree and that is why we are warning you. It is extremely rare that any brand of RO will deliver near its rated gallonage. If your family needs more than 5 gpd and only has a 45 psi inlet you might consider buying a larger than 30 gpd rated RO. If you only have 40 psi we strongly recommend purchasing a booster pump. This statement applies not only to the RO that we sell but also to the design of all brands of residential ROs. MOST families don't use over 2-5 gallons of RO drinking water and, most families are perfectly happy with a 30-gpd RO system. If your family and/or your water source isn't "typical" then we suggest getting a bigger than 15-30 gpd rated system. Realize that if you have at least 50-psi inlet, fairly clear, 77°F and have the produced water dribbling into a container then the system will probably deliver slightly more than the ratings. Since this is probably not the case, we want to let you know this before you buy an RO system. Inlet water is "squeezed" through the RO membrane. That is how the principle of any brand RO works. With all brands of reverse osmosis filters you need a good amount of pressure.

Q. "I bought an RO someplace else and the company went out of business. Can you help me?"
A. With many plumbing-related products we can help, but, with RO brands that we didn't sell, we can't (except with Culligan® and Kiss brand). If you purchased your RO elsewhere we cannot locate/find/get you a membrane or filter for your RO system.

Q. "Will the above r.o. systems that you offer pass my local new construction inspection?"
A. Since we ship throughout the entire U.S., and every state and local agency has their own guidelines (some have a local "agenda"), we can not possibly guarantee that your local agency will pass any of our r.o.'s. We suggest that if passing their "inspection" is a concern, that you print out the products page in question and take it to them. Simply show them the page and ask if they could possibly have a "problem" with that product before placing your order. If that agency has a special need or concern, then just contact us telling us what that concern is. Possibly we might be able to provide information for them, which might then alleviate their concerns. We only offer top quality plumbing products that are acceptable in most areas but that is not to say that we can guarantee that your local governmental body will "pass" any of our quality products.

Q. "I have hazardous water. Will an RO give me "pure" water?"
A. RO systems (no matter what brand) do not produce sterile water. Some microbial growth is common after an RO system. If your feed water has microbiological water problems then possibly an Ultra Violet water filtration system might be needed.

Q. "Ok, I installed my RO and have my faucet open but I'm not getting much water. I do hear water running down my waste pipe but I'm not getting much water out of my faucet. What is wrong?"
A. Nothing is probably wrong (assuming you purchased your RO unit from us). The reason for the tank on residential RO systems is because it takes a long time to produce RO water. The faucet needs to be in the off position and then the tank will (very slowly) fill. On the 30-gallon models it takes at least a day to produce up to 30 gallons. That is only slightly more than one gallon per hour. Close your faucet and wait at least an hour and then the tank will be partially full and you can then start to use water. A 30-gallon per day model does not mean that you can use 30 gallons all at once but rather, it can (if all was "ideal") produce up to 30 gallons during an entire 24-hour period. Please note that quite a bit of water is wasted by all brands of RO to produce RO water and that is why you are hearing the waste water running.

Q. "Whenever my R.O. system is recharging (such as after I fill a large container with the filtered water) the air gap filter makes a gurgling and sucking sound. Is this normal ?"
A. Noise with (any brand) of r.o. faucet air gap is normal and to be expected. Waste water is draining and so noise from the water passing through the air gap can not be eliminated totally. Shortening your tubing as much as possible should help diminish the noise to the lowest sound level possible. Please understand that the air gap is a kind of back-flow prevention device for your safety and so we never recommend by-passing your air gap.

Q. "My existing RO seems to work but when I want to get 3 gallons of water all at once it won't do it. Is this normal?"
A. Most residential RO systems come with a 2.5 (rated) gallon (or smaller) storage tank. Most won't hold that much water (will vary with pressures) but once your RO has filled that tank you "should" get at least one gallon of water from it. To increase the amount of water that you can get at once you can buy (and install) an additional RO water storage tank. We offer them on our ro parts page (#ROP-TANK) and that will increase your water holding capacity.

Q. "Must I get a permit to install a Reverse Osmosis system?"
A. It depends on your local plumbing codes and rules. Since we ship to so many different areas we simply can not "keep up" with the latest (seems like) ever changing local and state laws. We always recommend that you follow all laws and so, we recommend that you contact your local code enforcement governmental bodies to be sure of the laws concerning reverse osmosis in your area before purchasing any brand.

Q. "Are these reverse osmosis systems certified and rated?"
A. The WRO-2550 is certified under NSF/ANSI Standard 58. STANDARD 58: Reverse Osmosis Drinking Water Treatment Systems ANSI/NSF Standard 58 applies to systems where water is forced via pressure through a semi-permeable membrane. Most systems incorporate pre- and post- filters along with the membrane itself; these additional filters may be certified separately under the requirements of Standards 42 and/or 53 as applicable.

Q. "From your experience, do you have any additional reverse osmosis installation tips or hints?"
A. With any brand of RO system that has a carbon filter ahead of the membrane, we recommend that you disconnect the membrane and run the water through the carbon filter initially for at least five to ten minutes. Most carbon filters will dump some carbon at first and this can foul your membrane. Do this whenever you replace the carbon filter as well and you will save yourself some potential grief.

Q. "While I am buying an RO system from you should I order an extra membrane and carbon filters?"
A. Most people will not mention this (or do not know) but RO membranes have a shelf life. We highly recommend that you buy your RO membranes right before installing them and not to purchase extras until you need them. We take pride in offering not only today's replacement cartridges/membranes but we also offer replacements for units that we used to sell.

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