By Bill Herrera and Michael Pineda Jr., CWS-II

Subscribers’ to renowned industry publications, such as WC&P, are always looking for technical tips and techniques for system installations. In reality, there isn’t a single person who is considered the ultimate authority on residential RO installations; however, this article will examine the basic steps and requirements that will help ensure successful installations.

Tips of the trade

The most valuable tip has nothing to do with water quality or the technical type of reverse osmosis (RO) system utilized. It is simply focused on how to minimize risks.

The amount of risk liability that is caused by a damaging leak or disastrous flood is the same with a home RO installation as it would be with a large commercial or industrial application. Sometimes it is even greater when considering the high cost of homes today.

Both scenarios involve man-made devices under long-term variable pressures, and include other conditions such as oxidation, corrosion and mechanical wear. Not only must the installation be successful, but the longevity for returning business must also be successful.

Insurance requirements

Water treatment dealers need business liability insurance. Water treatment professionals are classified as plumbers (a very high-risk profession) by the insurance industry. An initial general liability policy is rather inexpensive forrecommended coverage of around $1.5 million or greater.

Workman’s compensation, on the other hand, is quite expensive, though it is not required in some statesand may be unnecessary for residential installations.

It is, however, often required for commercial installations such as office or apartment complex buildings.

It is recommended that an experienced industry insurance carrier be selected. One of the little unknown values of being a member of national and state water quality associations is of the availability of information about carriers familiar with the industry.

Product standards

The dilemma of choosing a National Sanitary Foundation (NSF) approved or non-approved product is a question faced by all members of the industry. Relative to single home installations, code requirements for NSF approved products can be vague and confusing to say the least. They may vary greatly from area to area.

The cost of an NSF-approved home RO system is typically greater than a non-approved product, though residential consumers don’t specifically ask for NSF certification. But one risk-reducing factor pertaining to NSF product approval is the current burst and cycle testing as provided under NSF/ANSI Standard 44.

Each NSF/ANSI standard for drinking water treatment units (DWTUs) requires structural integrity testing. Cycle pressure testing simulates water hammer (pressure surge) events that a product plumbed into a pressurized supply could experience in the field.

The test typically consists of 100,000 pressure cycles from zero to 150 psi (or the product’s maximum working pressure, whichever is greater).

Products designed for open discharge are tested with 10,000 cycles from zero to 50 psi.1

Having engineered and designed many of these same products in the past, many professional installers have first-hand knowledge concerning material integrity and the quality of the workmanship required to pass the Standard 44 protocol. Professionals will want this standard working for them.

Quality and tooling

Installation quality can also have an adverse effect on risk management. Knowing that you are likely to service the product for the next ten or so years, focus on the quality of work instead of the in-and-out speed.

To ensure a quality and timely installation, however, it is recommended the technician ‘tool up’ correctly prior to performing the operation. A dedicated tool kit specifically designed for residential RO installations should always be used.

It is recommended that an installer never share tools with other non-home RO jobs or some valuable requirements for the next installation may be missing. Likewise, service vehicles should travel with a parts kit specifically for the RO design being installed. At the minimum, the kits should include:

  • A drill, preferably with a right angle and variable speed option should be used for counter top preparation. Many prefer 110 VAC because there is almost always available voltage nearby, and many counter top installations will consume at least two drill batteries. Coincidentally, each may require a slow RPM when drilling. You may wish to keep a versatile battery powered drill just for under-counter, pilot hole preparation and hardware installation.
  • Specialty bits for all counter top applications should also be included in the installation kit. They should include hole knockouts for stainless steel, standard hole saws for man-made compositions and diamond core drills for both ceramic and granite counter tops.2
  • The bits in installation kits should be bullet style. These will outlast standard bits when used with stainless steel sinks. Never use multi-bits, for the same reason.
  • Jigs and templates are another key element. Not creating a pilot hole jig in order to mount the RO onto the counter wall is a mistake. An effective jig can be a simple contraption comprised of a flat wooden board and steelinserted pilot holes. Placing the jig upright under the counter assures the necessary height of the mounting installation and does not require a pre-pencil mark, since the pilot holes are often standard for the system.
  • Specialty feedwater line isolation valve tools are an important focus, as agreat percentage of RO system suppliers provide a saddle tapping / puncture style needle valve for RO feed isolation. This is a device clamped on malleable pipe with a tee handle for forcing a needle tip into the pipe, puncturing the feed-line and allowing for a pressurized supply. These often need replacement over the lifetime of the system due to electrolysis or water corrosion. A system isolation valve is always inline and hard plumbed. Various suppliers of RO systems have many different styles of valves and adaptor kits. You may want to keep several different styles in stock and try to be prepared with versatile valve tools for any connection you may encounter.
  • Specialty tools should be included in the home RO installation and service toolbox. Have tubing snips for cutting tubing and a long-nose pointed punch for hole scribing, especially when lining up the drain line, saddle clamp port to the sink drain hub. A tee-handled swivel wrench is used for tightening the faucet nut to the sink top. FDA qualified silicon lubricant is used to lightly lube cartridge filter o-rings (if present) and bowl o-rings. Filter bowls should only be hand tightened. Regularly rotate the bowl o-rings with a fresh set during routine service. (Don’t throw the old o-rings away. They will eventually un-flatten and return to their original size.) A graduated cylinder is needed to verify the RO waste to drain flow rate. Sometimes start-up debris will clog the waste to drain flow control orifice, thus make sure to verify that the flow to drain is present.
  • Pressure regulator installation: If static pressure is above 80 psig, the installation will most likely require a pressure regulator. Pressure may climb above 100 psig in the late evening. It is best to install a full house pressure regulator outdoors, thereby minimizing a leak risk indoors. You may also want to keep a signed document on-file indicating the customer’s refusal to follow such regulator advice.

Some tricks of the trade

The following insider’s help list includes helpful hints gleaned from seminars, shows and factory representatives.

The Paper Towel Trick

Once the installation is completed and the system is pressurized, place flat paper towel sheets under the installation. A homeowner will have trouble identifying a leak immediately after start-up, sothe paper towel trick will help them easily identify a drip. Suggest that the homeowner call if they see a wet spot on the paper towel, and also ask them to inspect the paper towel before the next day’s courtesy call follow-up.

The Drain Line Trick

Every once in a while, installers will encountere a stubborn, louder than normal drain flow gurgle. Enlarging the drain hole from the quarter- inch standard to 7/16 inch allows the flow to trickle down the connection and will, in most cases, solve the gurgling problem.

The Pre-Charge Trick

Some operations pretest the system on bench tops prior to installion, as it reduces leak risk and also pre-rinses the membrane for the customer on start-up. You can also pre-charge a rotational bladder tank, immediately providing purified water in volume to the customer upon installation.

The Upside Down Technique. Sometimes the automatic shutoff diaphragm valve vibrates when in operation. Usually the air in the system is causing this vibration and will eventually work its way out. To help purge the air, completely spin the system upside down for a few seconds. Always tidy-up the installation by trimming the excess tubing length. Do not trim the tubing too short; grab-ring speed fittings are not designed for hard curved tubing connections. They may leak, or worse work their way out over time. Clear any tubing from the pull sink hose water sprayer line and use tie-wraps where necessary.

By following the above suggestions customers will appreciate the extra attention and your professionalism will shine through. Remember to place contact information near the unit for future service business. Don’t forget to make the customer aware of additional products and services that are available. The goal of a long-term successful account can be accomplished.


  1. Unger, Mark T. “Can You Handle the Pressure?” Water Quality Products October 2007 Volume 12, Number: 10

About the authors

Bill Herrera, owner of Water Resources Co. (WRC) based in San Antonio, Texas, Herrerra has over 25 years of water treatment experience throughout various aspects of the water purification industry. He holds a Bachelor of Science degree in industrial engineering , serves as a technical writer for several trade publication magazines and provides business technical presentations and training throughout the US, Latin America, Asia and Australia.Herrera is a board-recommended technical consultant for the American Water Quality Association. Contributing author Michael Pineda Jr. CWS-II is a National Account Manager for Water Resources Co. managing over 200 on-going 24-hour commercial RO accounts. He may be contacted at (210) 698-8960.

About the company

Water Resources Co. specializes in solving water problems. The company focuses on engineering and designing water purification systems for commercial, industrial and municipal applications. The staff of professionals has over 320 years of combined experience to offer its customers.


Comments are closed.