Reverse Osmosis Treatment Systems
Using RO for Contaminated Drinking Water

What contaminants do reverse osmosis water treatment systems remove?

Reverse Osmosis " filters" like the compact RO system show at left themselves do not remove aesthetic contaminants such as dissolved chemicals, odors or bad tastes in the water supply.

For this reason some reverse osmosis water treatment systems include additional stages of pre or post filtering to remove bacteria, chemicals, odors, tastes.

Reverse Osmosis Water Treatment System Clogging

Watch out for water high in bacterial contamination. Reverse osmosis systems are not usually recommended for water supplies that are high in bacterial contamination because bacteria build-up on the input side of the RO filter tend to block and clog the system.

Watch out: also for water supplies high in sediment, debris, chemicals, odors, or bad tastes.

To avoid clogging the RO system a pre-filter to remove sediment may be needed, and to avoid chemical, taste, or odor complaints, a post-processing charcoal filter system may also be needed.

Reverse osmosis (RO) water purifiers (see sketch at below left) will remove nearly all water contaminants and also remove minerals from water leaving it soft and purified.

Reverse Osmosis Purifiers as Water Softeners

Unlike a conventional salt-based water softener, RO systems do not discharge salt into the drain system, though they do discharge four gallons of waste water for every gallon of purified water produced.

Because the design and capacity of various RO systems varies, only if a reverse osmosis system is registered and listed as a water purifier, can it be relied on to handle bacterial contamination in the water supply.

Disposal of Reverse Osmosis Water Purifier Concentrate

As it becomes high in contaminants, water on the input side of the RO filter is flushed to a disposal location.

See REVERSE OSMOSIS CONCENTRATE WASTE DISPOSAL for a discussion of the effects of disposing of reverse osmosis water treatment equipment wastewater - RO concentrate - into septic tanks and drainfields.

OPINION: this method works well for some contaminants, as a point-of-use system. RO wastes quite a bit of water and does not address some chemical contaminants.

We don't know (yet) which uses more discharge water - a water salt-based water softener or an RO system. That's because the quantity of water "wasted" by a reverse osmosis system depends on the quantity of water that is demanded from its output side.

Operating Requirements, Pressure, Temperature for Reverse Osmosis Systems

Reade Question: what is the water tank height needed for a reverse osmosis system installation?

(June 6, 2015) HARI KRISHNA PODARALLA said:

What shall be the minimum height at which a water tank shall be placed, the tank from which a RO + UV water filter,draws water.

This question was posted originally at WATER FILTERS, HOME USE

Reply: not height but feedwater operating pressures for RO systems are important

Hari I have not seen such a requirement; water is delivered to the filter by building water pressure; as long as the RO system you're installing is receiving adequate building water pressure it'll work.

A reverse osmosis system, to work, does need good water pressure.

Typical home reverse osmosis water filter systems are designed to function

• between 30 psi and 100 psi of supply water pressure and
• at temperatures between 40° and 90° F.
  - "Referse Osmosis Membrane Operating Conditions and Performance Data", ESP Water Products 2460 McIver Lane, #200 Carrollton, TX 75006, Tel: 877-377-9876, Email,: customersupport@espwaterproducts.com, retrieved 11/9/2015 original source https://www.espwaterproducts.com/reverse-osmosis-membrane-operating-conditions/

Best would be water pressure around 60 psi - a figure high enough to overcome the osmotic pressure and to cause the reverse-osmotic flow of water. This pressure (60 psi) is within the operating range of some but not all well pump systems.

Note that I'm talking about RO system operating pressure (referred to by the RO people as "feedwater pressure") for a typical residential referse osmosis system. The actual pressure requirements for your system may also depend on the filter type your RO system uses (Cellulosic, aromatic polyamide, or thin film composite).

RO System Water Hardness Operating Range

The water hardness handled by RO systems is typically 0 to 350 mg/L or under 20 grains of hardness per gallon (gpg) - ESP Op.Cit.

RO System Water Supply Iron, Manganese, Hydrogen Sulfide, and Chlorine Content Operating Range

RO systems whose specifications we reviewed operate at the following chemical level ranges, that is, will work accepting water with these levels of chemicals:

• Chlorine - zero (i.e. none needed)
• Hydrogen Sulfide (H2S) "sulphur odors" - 0.1 to 10.0 mg/L
• Manganese (Mn) - 0.00 mg/L (some systems may offer a different numbrer - Ed).
• Iron (Fe) - 0 to 0.05 mg/L - ESP Op.Cit.

RO System Ph Operating Range

Depending on the system type and water source (community, private well and other codes that may apply) RO systems operate in the pH Range of 3.0 to 11.0. Note that the specifications for operation of any RO system depend also on the filter type that is in use. - ESP Op.Cit.

RO System Operating Pressures for Desalination of Water for Drinking

An RO system used for salt water de-salination operates at much higher pressures, ranging from 250-400 psi for grackish water to 800-1000 psi for the desalination of seawater. - "Desalination by referse osmosis", Organization of American States, OAS, retrieved 11/9/2015 original source: https://www.oas.org/dsd/publications/Unit/oea59e/ch20.htm

RO System Supply Water Turbidty Operating Range

RO systems whose specifications we reviewed operate at any turbidity level under 1.0 Net Turbidty (NTU) - an expression of the maximum level of total dissolved solids (TDS) in the water supply.

Reverse Osmosis Water Products, Treatment, Research

• NSF/ANSI 58 - 2015, "Reverse osmosis drinking water treatment systems", http://webstore.ansi.org/RecordDetail.aspx?sku=NSF%2FANSI+58-2015, obtained through the contact information given in the citation just above.
• Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..."- review excerpts
  
  This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals.
• HANS REVERSE OSMOSIS WATER TREATMENT SYSTEM MANUAL [PDF] HANS Power & Water, LLC 38955 Hills Tech Drive Farmington Hills, MI 48331 Sales: (833)333-4267 Service: (888)986-4156 Web: hanspremiumwater.com
• Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
• Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
  by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998. - review excerpts
  
  "This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors."
  
  The Pharmaceutical Journal: "This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ...
  
  This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended." The Journal of Hospital Infection.: "The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ...
  
  The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians."
  
  New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods.

Effectiveness of RO or Reverse Osmosis water treatment

In general, RO is highly-effective in removing most contaminants from water, though as you'll see in research below, there may be undesirable health effects of drinking de-mineralized water, of metal pipe corrosion, and possibly of leaching lead from certain plastic piping products.

• Beall, Gary W. "The use of organo-clays in water treatment." Applied Clay Science 24, no. 1 (2003): 11-20.
• Childress, Amy E., and Menachem Elimelech. "Effect of solution chemistry on the surface charge of polymeric reverse osmosis and nanofiltration membranes." Journal of Membrane Science 119, no. 2 (1996): 253-268.
• Davison, A. M., H. Oli, G. S. Walker, and A. M. Lewins. "Water supply aluminium concentration, dialysis dementia, and effect of reverse-osmosis water treatment." The Lancet 320, no. 8302 (1982): 785-787.
• Drewes, Jörg E., Martin Reinhard, and Peter Fox. "Comparing microfiltration-reverse osmosis and soil-aquifer treatment for indirect potable reuse of water." Water Research 37, no. 15 (2003): 3612-3621.
• Duranceau, Steven J. "Membrane practices for water treatment." (2001).
• Fritzmann, C., J. Löwenberg, T. Wintgens, and T. Melin. "State-of-the-art of reverse osmosis desalination." Desalination 216, no. 1 (2007): 1-76.
• Gagliardo, Paul, Samer Adham, Rhodes Trussell, and Adam Olivieri. "Water repurification via reverse osmosis." Desalination 117, no. 1-3 (1998): 73-78.
• Greenlee, Lauren F., Desmond F. Lawler, Benny D. Freeman, Benoit Marrot, and Philippe Moulin. "Reverse osmosis desalination: water sources, technology, and today's challenges." Water research 43, no. 9 (2009): 2317-2348.
• Hyung, Hoon, and Jae-Hong Kim. "A mechanistic study on boron rejection by sea water reverse osmosis membranes." Journal of Membrane Science 286, no. 1-2 (2006): 269-278.
• Kang, Guo-dong, and Yi-ming Cao. "Development of antifouling reverse osmosis membranes for water treatment: a review." Water research 46, no. 3 (2012): 584-600.
• Li, Xiao-yan, and Hiu Ping Chu. "Membrane bioreactor for the drinking water treatment of polluted surface water supplies." Water Research 37, no. 19 (2003): 4781-4791.
• Malaeb, Lilian, and George M. Ayoub. "Reverse osmosis technology for water treatment: state of the art review." Desalination 267, no. 1 (2011): 1-8.
• Mondal, S., and S. Ranil Wickramasinghe. "Produced water treatment by nanofiltration and reverse osmosis membranes." Journal of Membrane Science 322, no. 1 (2008): 162-170.
• Nicolaisen, Bjarne. "Developments in membrane technology for water treatment." Desalination 153, no. 1 (2003): 355-360.
• Ning, Robert Y. "Arsenic removal by reverse osmosis." Desalination 143, no. 3 (2002): 237-241.
• Park, Se-keun, and Jiang Yong Hu. "Assessment of the extent of bacterial growth in reverse osmosis system for improving drinking water quality." Journal of Environmental Science and Health Part A 45, no. 8 (2010): 968-977.
  Abstract excerpt:
  
  These observations can be indicative of possibilities for bacterial growth in the RO permeate water with easily assimilable organic carbon concentrations below values proposed for biostability. RO permeate water does not appear to be biologically stable water.
  
  Therefore, efforts to minimize bacterial growth in the RO permeate water and in the distribution system must consider post-disinfection.
• Petersen, Robert J. "Composite reverse osmosis and nanofiltration membranes." Journal of membrane science 83, no. 1 (1993): 81-150.
• Radjenović, J., M. Petrović, F. Ventura, and D. Barceló. "Rejection of pharmaceuticals in nanofiltration and reverse osmosis membrane drinking water treatment." Water Research 42, no. 14 (2008): 3601-3610.
• Rautenbach, R., and Th Linn. "High-pressure reverse osmosis and nanofiltration, a “zero discharge” process combination for the treatment of waste water with severe fouling/scaling potential." Desalination 105, no. 1 (1996): 63-70.
• Reynolds, Kelly A., Kristina D. Mena, and Charles P. Gerba. "Risk of waterborne illness via drinking water in the United States." Reviews of environmental contamination and toxicology. Springer New York, 2008. 117-158.
• Tran, Thuy, Brian Bolto, Stephen Gray, Manh Hoang, and Eddy Ostarcevic. "An autopsy study of a fouled reverse osmosis membrane element used in a brackish water treatment plant." Water research 41, no. 17 (2007): 3915-3923.

What are the health effects of drinking RO-treated water?

• Abejón, A., A. Garea, and A. Irabien ARSENIC REMOVAL from drinking water by reverse osmosis: Minimization of costs and energy consumption [PDF] Separation and Purification Technology 144 (2015): 46-53.
  Abstract:
  Arsenic is one of the most serious inorganic contaminants in drinking water on a worldwide scale. To comply with the MCL (maximum contaminant level, 10 μg/l arsenic in drinking water) established by the World Health Organization, numerous techniques have been studied, such as ion exchange, coagulation and flocculation, precipitation, adsorption and membrane technologies.
  
  Among the available technologies applicable to water treatment, membrane filtration has been identified as a promising technology to remove arsenic from water. The goal of this study is to demonstrate the technical and economic viability of removing arsenic (V) using an optimized reverse osmosis process, with minimization of the total cost as the objective of the optimization strategy.
  
  The optimization results showed that the total costs of a two-stage membrane cascade used for the removal of arsenic (V) from drinking water for a population of 20,000 inhabitants were 1041 $/d and 0.52 $/m3 of drinking water produced.
  
  Energy consumption was the most relevant cost, corresponding to 35% of the total cost. Sensitivity analysis was performed to determine the total costs of the installation for different scenarios in terms of drinking water production: (i) 0.44–0.56 $/m3 for electricity prices of 0.05–0.10 $/KW h; (ii) 0.88–0.45 $/m3 for populations ranging from 5000 to 50,000 inhabitants; and (iii) 0.52–0.61 $/m3 when the membrane lifetime was reduced from 3 to 1.5 years.
  
  The multiobjective optimization solutions, which consider the best compromises among the quality and cost objectives, indicated that the concentration of As (V) in the permeate water can be reduced to 0.5 μg/l at a feasible cost.
• Imbulana, Sachithra, Kumiko Oguma, and Satoshi Takizawa. "Evaluation of groundwater quality and reverse osmosis water treatment plants in the endemic areas of Chronic Kidney Disease of Unknown Etiology (CKDu) in Sri Lanka." Science of The Total Environment 745 (2020): 140716.
• Linge, Kathryn L., Palenque Blair, Francesco Busetti, Clemencia Rodriguez, and Anna Heitz. "Chemicals in reverse osmosis-treated wastewater: occurrence, health risk, and contribution to residual dissolved organic carbon." Journal of Water Supply: Research and Technology—AQUA 61, no. 8 (2012): 494-505.
  Abstract:
  The quality and safety of reverse osmosis (RO)-treated secondary wastewater (WW), for indirect potable re-use, was assessed using a dataset of 375 chemicals measured in RO-treated WW. A screening health risk assessment indicated that four N-nitrosamines were of potential concern, although median concentrations of these chemicals were always below health values.
  
  The most frequently detected chemicals in RO-treated water were disinfection by-products, volatile organic compounds, metals and complexing agents, in contrast to many monitoring programmes that focus on pharmaceuticals, personal care products and hormones.
  
  Frequent detections in RO-treated WW were most related to high concentrations in secondary WW, relative to limit of reporting, and the potential for chemicals to form or be added during the treatment process, rather than poor rejection by RO membranes.
  
  Between 3.7 and 10.7 μg/L of dissolved organic carbon (DOC) in RO permeate could be attributed from chemicals detected on at least one occasion, with the majority of this total attributed to chemicals detected in less than 25% of samples.
  
  While chemicals below detection may contribute a significant component of DOC, it is likely that natural organic matter and soluble microbial products still contribute the majority of DOC to RO permeate.
  
  A high degree of safety is demonstrated for the use of RO-treated WW as an indirect source of potable water.
• NSF / ANSI 53 - 2015, "Drinking Water Treatment Units Health Effects", NSF or ANSI, ANSI Customer Service contact information: Email: info@ansi.org Phone: 212.642.4900, 212.642.4980 ANSI Attn: Customer Service Department 25 W 43rd Street, 4th Floor New York, NY, 10036, http://webstore.ansi.org/RecordDetail.aspx?sku=NSF%2FANSI+53-2015
• Payment, Pierre, E. D. U. A. R. D. O. Franco, Lesley Richardson, and Jack Siemiatycki. GASTROINTESTINAL HEALTH EFFECTS ASSOCIATED WITH THE CONSUMPTION OF DRINKING WATER PRODUCED BY POINT-OF-USE DOMESTIC REVERSE-OSMOSIS FILTRATION UNITS [PDF] Applied and Environmental Microbiology 57, no. 4 (1991): 945-948.
  Abstract:
  
  During a prospective epidemiological study of gastrointestinal health effects associated with the consumption of drinking water produced by reverse-osmosis domestic units, a correlation was demonstrated between the bacterial counts on R2A medium incubated at 35 degrees C and the reported gastrointestinal symptoms in families who used these units.
  
  A univariate correlation was found with bacterial counts on R2A medium at 20 degrees C but was confounded by the bacterial counts at 35 degrees C. Other variables, such as family size and amount of water consumed, were not independently explanatory of the rate of illness.
  
  These observations raise concerns for the possibility of increased disease associated with certain point-of-use treatment devices for domestic use when high levels of bacterial growth occur.
• Saini, Rummi Devi. HEALTH RISKS FROM LONG TERM CONSUMPTION OF REVERSE OSMOSIS WATER [PDF] International Journal of Applied Chemistry 13, no. 2 (2017): 293-301.
  Abstract:
  The popularity of reverse osmosis (RO) water has been steadily increasing since it was first introduced as a home water purification system in the 1970s. Even the bottle water companies are also using reverse osmosis water these days.
  
  Reverse Osmosis (RO) is a membrane based process technology used for desalination of water to make it drinkable.
  
  The RO water purification method involves the process of forcing the water through a semipermeable membrane, which filters out contaminants larger in size than water molecules.
  
  The most mineral particles that are required by our body such as sodium, magnesium and iron are larger in size than water molecules and get removed from water by semipermeable membrane of the RO system thus render water unhealthy for consumption.
  
  The World Health Organisation has conducted a study which exposes some of the health risks associated with demineralised drinking water. Some of the health risks associated with consuming reverse osmosis water are discussed here.
• Schoeman, J. J., and A. Steyn. "Nitrate removal with reverse osmosis in a rural area in South Africa." Desalination 155, no. 1 (2003): 15-26.

What are the effects of RO treated water on building piping?

• Beale, David J., Michael S. Dunn, Paul D. Morrison, Nichola A. Porter, and David R. Marlow. "Characterisation of bulk water samples from copper pipes undergoing microbially influenced corrosion by diagnostic metabolomic profiling." Corrosion Science 55 (2012): 272-279.
• Liang, Juan, Anqi Deng, Rongjing Xie, Mylene Gomez, Jiangyong Hu, Jufang Zhang, Choon Nam Ong, and Avner Adin. "Impact of flow rate on corrosion of cast iron and quality of re-mineralized seawater reverse osmosis (SWRO) membrane product water." Desalination 322 (2013): 76-83.
  Abstract:
  Remineralization of desalinated water as part of post-treatment has attracted great attention lately because of the need for high quality water and for the protection of the network pipelines.
  
  Laboratory experiments of remineralization using Ca2 + and Mg2 + containing substances were carried out to investigate the effect of flow rates on corrosion behaviour of cast iron coupons and water quality of re-mineralized SWRO product under tropical conditions. Experiments demonstrated the clear effect of increased corrosion rate at higher flow rate, i.e., the flow rate of 1, 10 to 20 L/d increased the corrosion rate from 4.72, 6.74 to 9.17 mpy, respectively.
  
  The turbidity and apparent colour of flow rate at 1 L/d were much higher than those of 10 and 20 L/d because of iron rusting materials formation and accumulation at the low flow rate. Cast iron corrosion and various flow rates did not significantly influence water quality parameters associated with SWRO product remineralization, such as total alkalinity and hardness.
  
  Microstructure observation showed that the main corrosion product was small crystalline globules of lepidocrocite, which formed a thick orange layer on coupon surface. Crystal fiber of white calcium composite was also found on some areas of the coupon surface which functioned as a protective layer.
• McCutchan, Joseph W., and James S. Johnson. "Reverse Osmosis at Coalinga, California." Journal (American Water Works Association) (1970): 346-353.
• Shrestha, Jyotsna. INFLUENCE OF PERMEATE FROM DOMESTIC REVERSE OSMOSIS FILTERS ON LEAD CORROSION AND LEACHING FROM PLASTIC PIPES PhD diss., The University of Wisconsin-Milwaukee, 2016.
• Shi, Baoyou, and James S. Taylor. "Iron and copper release in drinking-water distribution systems." Journal of environmental health 70, no. 2 (2007): 29-36.
  Abstract:
  A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs).
  
  The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes.
  
  Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release.
  
  The iron release of desalinated water was relatively high because of the water’s high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature.
• Shi, Baoyou, Weizhong Xiao, and James S. Taylor. "Influences of water treatment process on iron and copper release in distribution system." Journal of Environmental Science and Health Part A 41, no. 8 (2006): 1667-1683.
• Slaats, P. G. G., H. Brink, and T. J. J. van der Hoven. "Copper corrosion control in the Netherlands." Water Science and Technology: Water Supply 1, no. 3 (2001): 75-82.
• Tularam, Gurudeo Anand, and Mahbub Ilahee. "Environmental concerns of desalinating seawater using reverse osmosis." Journal of Environmental monitoring 9, no. 8 (2007): 805-813.

Manufacturers / Suppliers of Reverse Osmosis Water Treatment Systems

Illustration: A combination filtration and revese osmosis water purification system from Applied Membranes, Inc., listed below.

Note that some of the RO equipment producers below specialize in commercial or industrial RO systems (noted in parentheses).

• American Water - Kinetico Water Systems, Web :
• AmeriWater Purification Co., 3345 Stop 8 Rd., Dayton OH USA Web: ameriwater.com (Industrial & health care)
• Applied Membranes, Inc., RO Systems, 2450 Business Park Dr. Vista, CA 92081-8847 USA, Tel: 800-0291-9321 Web: appliedmembranes.com
• APEC Water Systems, 301 Brea Canyon Rd, City of Industry, CA, USA Web: freedrinkingwater.com/products
• Aquatech RO Systems, high efficiency RO systems for water desalination systems
• Axeon Water Systems, 40980 County Center Drive, Temecula, CA 92591 USA, Tel: 800-320-4074 Web: axeonwater.com
• Bioprocess H2O, 45 Highpoint Ave # 3, Portsmouth, RI USA Web: bioprocessh2o.com
• Centec (Centec GmbH), RO Systems, Web: centec-usa.com/datasheet-reverse-osmosis (Commercial RO systems)
• Complete Water Solutions, 851 MainSt., Twin Lakes WI, USA Web: complete-water.com/solutions/reverse-osmosis (Industrial applications)
• Culligan Water Treatment Systems - Note that there are multiple "Culligan Water Treatment & Water Softening" companies across the U.S., e.g.
  
  Culligan of Rockland, 21 First St., New City, NY, USA Web: culliganrockland.com/
  
  Culligan Water of New Jersey, Web: ulligannj.com/drinking-water-coolers/reverse-osmosis-drinking-water-systems
  
  Reynolds Culligan, 119 Franklin St., W. Reading PA, USA Web: reynoldsculligan.com (Commercial & industrial RO systems)
• Dow Chemical Co. RO systems
• Dupont Water Solutions, Tel: 833-338-7668 Web: dupont.com/water/technologies/reverse-osmosis-ro.html
• Ecolife Technologies, 1951 Lynx PL, Ontario CA 91761, Waterdrop RO Systems, Email: service@waterdropfilter.com Tel: 888-352-3558 Web: waterdropfilter.com Manufacturer: Qingdao Ecopure Filter Co., Ltd.No. 13, Yishengbai Road, Environmental Protection Industry Zone, Jimo, Qingdao, 266201, China
• ESP Water Products, 3845 Forney Rd. Ste B, Mesquite TX, USA Web: espwaterproducts.com/understanding-ro/ (Commercial RO systems)
• Evoqua Water Technologies, 210 Sixth Avenue, Suite 3300, Pittsburgh,PA, USA web: evoqua.com (Industrial & residential?)
• GE Water and Process Technologies
• ** IQS Directory: Industrial Wuick Search Reverse Osmosis Manufacturers & Suppliers, lists Reverse Osmosis Systems suppliers. Web: iqsdirectory.com/reverse-osmosis-water-filter/
• Kissane Water Conditioning, 2512 Burnet Ave, Syracuse, NY USA, Web: kissanewater.com/reverse-osmosis-systems/
• Koch Membrane Systems, Inc., Wilmington MA, USA (Commercial RO systems)
• Membrane System Specialists, Inc., 7474 Integrity Way, Wisconsin Rapids WI, USA, Web: mssincorporated.com/filtration-systems/ (Industrial, food, dairy)
• Nancrede Engineering Co., Web: necoindustrialwater.com (Commercial RO systems
• NuAqua RO Systems, 735 Challenger St., Brea CA 92821 USA, Tel: 888-621-0460, Email: support@nuaquasystems.com Web: nuaquasystems.com
• Paragon Water Systems, Paragon Water Systems, Inc.13805 Monroes Park Tampa, FL 33635 USA Tel: 00-288-9708 Web: paragonwater.com
• PurePro Rerverse Osmosis Equipment Co., US Branch Office: 19636 S. 97th Ave Mokena, Illinois, U.S.A. Tel: +1 708 479 4473 Fax: +1 708 479 4332 www.purepro.net Web: pure-pro.com (company headquarters in Kaohsiung, Taiwan)
• Ransohoff Cleaning Technologies Group, 4933 Provident Drive, Cincinnati, OH, USA Web: ctgclean.com/water-pre-treatment
• ** RO-System.org lists & reviews Reverse Osmosis System Suppliers: Web: ro-system.org
• SAMCO RO systems, Web: samcotech.com (Commercial/Industrial)
• Syntec Corporation, 4060 N. DuPont Hwy., New Castle,  DE, USA, Web: syntec.com/watermotiv-pre-treatment
• US Water Systems, Inc., RO Systems, 1209 Country Club Rd, Indianapolis, IN 46234 USA, Tel: 855-923-6913 Web: uswatersystems.com (Residential & Commercial)