Residential Water Treatment Products And Installation Issues

By Rick Andrew, NSF International

Water treatment products encompass a broad array of technologies taking shape across a wide range of configurations. In their simplest form, these products require little to no installation. A pitcher or carafe filter, for instance, is not connected to the plumbing whatsoever. And almost anyone can handle installation of a faucet mount device that threads onto the end of the spout.

At the other end of the spectrum, some products can have complicated installations requiring permanent plumbing connections, bypass valves, waste lines and other requirements. These types of installations can prove challenging even to experienced do-it-yourself consumers, thus creating opportunities for plumbing contractors. Many homeowners shy away from plumbing work, understanding full well the consequences of leaky connections (or the inability to cook dinner because the unsuccessful installation attempt resulted in no water for the house!).

A number of installation issues and requirements are addressed through the NSF/ANSI Drinking Water Treatment Unit (DWTU) Standards, facilitated by NSF International. Seven of these standards address residential water treatment equipment (see Table 1). A voluntary, consensus process involving manufacturers, regulators and users of water treatment equipment is used to develop the requirements for these standards. The result is a thoughtful set of requirements that establish minimum, but conservative, requirements for material safety, structural integrity, general performance, contaminant reduction performance, and product literature.

Installation - Issues And Requirements: Following are some installation issues that can arise with different types of water treatment equipment, and how the NSF/ANSI DWTU Standards address them.

A point of note is that the standards do not directly address specific plumbing requirements, because there are multiple plumbing codes in the United States. What may be acceptable practice in one jurisdiction with one code may not be acceptable in other jurisdictions with other codes. Because of the varying requirements across the United States, and to accommodate international installations, the standards defer to state or local plumbing codes. The specific language requires the system and installation to comply with state and local laws and regulations. This language is required to be included in the installation, operation and maintenance instructions.

Plumbing codes can be a consideration for any under-the-sink-style systems that may be sold with self-piercing saddle valves. These valves are easy for homeowners to use, but do not meet plumbing code requirements in many areas. Before using a self-piercing saddle valve, make sure it meets code. There are many alternatives that are hard-plumbed to the cold water line that are also acceptable per the plumbing codes.

Under-the-sink-style systems (categorized as “plumbed-in to separate tap” in the NSF product listings) have auxiliary side faucets. Installation of these faucets usually requires drilling holes in countertops or sinks. Drilling holes in laminate counter tops is relatively simple, but trickier with stainless steel. A mistake on a granite countertop could end up being a costly one. Be sure your measurements and placement are correct, and your equipment and drill bits are appropriate to the task before drilling these surfaces.

Another consideration with under-the-sink systems is ease of filter replacements. Installation far back under the sink, or too close to the cabinet bottom, can make filter changes very difficult. Keep this in mind as you try to install the system near the front of the cabinet, high enough from the cabinet bottom to facilitate filter changes.

Water softeners, backwashing filters and reverse osmosis systems have drain lines for wastewater. These drain lines must have an air gap to prevent backsiphoning of wastewater into the system. Not only is an air gap required by plumbing codes, but also it is critical to the health of the homeowners. Contamination of water treatment equipment with wastewater can lead to microbiological contamination, and severe gastrointestinal illness.

Many reverse osmosis systems have a faucet with a built-in air gap, which eliminates the need for external air gap features. Standard 58 has a test requirement for air gap faucets. The protocol involves submerging the faucet in water, and drawing the water down to the critical level of the air gap through the outlet side of the device with a vacuum pump operating with a vacuum of 25 inches of mercury. Then, the vacuum pump is moved to the inlet side of the device and the vacuum is reapplied, and observed to ensure that water is not drawn across the gap.

Outside faucets and sprinkler systems should be teed off prior to any point-of-entry (POE) (whole house) treatment system being installed. There is no point in treating water that is going to outside taps or to water the lawn.

Certified systems are required to have detailed installation instructions in the manual. Be sure to consult the manual for the product when installing, as the manufacturer has put great care into making the installation as clear and easy as possible by following the instructions.

Any systems that regenerate or backwash will create wastewater that must be discharged. There are widely varying regulations regarding how this water is to be disposed of. Options include dry wells, sanitary sewers, septic systems, and other means. Be sure to check with the specific appropriate jurisdiction to be sure your installation is in accordance with regulations.

Pressure loss is a concern with POE systems. There are varying requirements for pressure loss under the NSF/ANSI DWTU Standards. For instance, Standard 44 requires that systems have a pressure drop not greater than 15 psig at the rated service flow. Standards 42 and 53 have the same requirement, except for systems that have built-in flow control devices. Those systems must achieve a flow rate of at least 4 gpm with a 30 psig inlet pressure. Standard 55 has no pressure drop requirement, and specifies that Class A UV systems must include a flow control device.

Whatever POE system you install, consideration of potential water demand and pressure drop is a must. Many plumbing codes deal with these issues in terms of sizing requirements, but sizing requirements alone may not suffice if the systems have flow control devices.

When evaluating treatment systems, verification of the product's quality, safety, durability and ability to perform as advertised is important. One good way to assure that water treatment products are both safe and effective is to use NSF-certified water treatment devices. When you find the NSF mark on the product or on its packaging, you can be assured that the product has undergone rigorous testing according to the applicable NSF/ANSI Standard(s).

This testing includes extraction testing for material safety, contaminant reduction testing to verify the manufacturer's claims of performance, and structural integrity testing to verify the ruggedness and durability of the product. Additionally, NSF certification requires that ongoing audits of manufacturing facilities are being conducted to verify ongoing continuity in manufacturing.

Proper Installation Is Essential: There is a reason many homeowners shy away from installing water treatment equipment - they are afraid of screwing it up! So many problems can arise from poor installation jobs, including leaks, lack of pressure, difficulty in servicing the system, backsiphoning of wastewater and more. Recognizing this reality, even many avid do-it-yourself homeowners call on professionals to handle these installations.

As a professional, installation of water treatment equipment may not be your main line of business. It is important to be aware of potential issues that can arise from these projects, so that you as a professional achieve excellent results, and do not end up suffering any of the pitfalls that the amateurs wish to avoid!

Table 1: NSF/ANSI Drinking Water Treatment Unit (DWTU) Standards

Technology
Adsorption / Mechanical Filtration
NSF/ANSI Standard
42 and 53
Description of Product Technology
Adsorption is the physical process that occurs when liquids, gases, dissolved or suspended matter adhere to the surface of, or in the pores of, an adsorbent medium. Mechanical filtration is a sieving concept, whereby large particles cannot pass through small pathways in the filter. Carbon filters and others use these technologies to filter water.

Technology
Softeners
NSF/ANSI Standard
44
Description of Product Technology
Water softening devices covered by Standard 44 use a cation exchange resin, regenerated with sodium chloride or potassium chloride, to reduce the amount of hardness (calcium, magnesium) in the water. The hardness ions in the water are replaced with sodium or potassium ions.

Technology
Ultraviolet Treatment
NSF/ANSI Standard
55
Description of Product Technology
This treatment style uses ultraviolet light to disinfect water (Class A systems) or to reduce the amount of heterotrophic bacteria present in the water (Class B systems).

Technology
Reverse Osmosis
NSF/ANSI Standard
58
Description of Product Technology
A process that reverses, by the application of pressure, the flow of water in a natural process of osmosis so that water passes from a more concentrated solution to a moredilute solution through a semi-permeable membrane. Most reverse osmosis systems incorporate pre- and post-filters along with the membrane itself.

Technology
Distillers
NSF/ANSI Standard
62
Description of Product Technology
These systems vaporize water and then collect the water vapor as it condenses, leaving many of the contaminants behind, particularly the heavy metals. Some contaminants that convert readily into gases, such as volatile organic chemicals, may be carried over with the water vapor.

Technology
Shower Filters
NSF/ANSI Standard
177
Description of Product Technology
These systems reduce free available chlorine (FAC) in shower water.

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Rick Andrew has been with NSF International for seven years, working with certification of residential drinking water products. He is the operations manager of the Drinking Water Treatment Units Program, having previously served as technical manager for four years. His prior experience was in the area of analytical and environmental chemistry consulting. Andrew has a bachelor's degree in chemistry and an MBA from the University of Michigan. He can be reached at 800/NSF-MARK or e-mail: Andrew@nsf.org.