Plumbing Industry


The American National Standards Institute (ANSI) is a not-for-profit, non-government organization that oversees the creation and use of voluntary health and safety standards for products and businesses across nearly all sectors of the U.S. economy.


An ancient alloy, composed primarily of copper and zinc, used in the manufacture of faucets and other plumbing fittings. Small amounts of other alloying materials are also added for various types of brass to address the requirements of specific applications. Brass is also the term for a faucet finish, also known as polished brass.


One of the basic elements (Cu), copper is used for plumbing piping, and is one of the alloys used to make brass, a key material in the manufacture of faucets and fittings.


A device designed to control and guide the flow of water. Examples include faucets, shower heads, shutoff valves, shower valves, and drinking fountain spouts. Some people call these "fixtures," but that term means something different to the plumbing industry. The differing usage of "fitting vs. fixtures" can lead to unintended consequences, such as when legislation calls for changes in fixtures, although the true intent involves changes in fittings. (See "Fixtures.")


A device for receiving water and/or waste matter that directs these substances into a sanitary drainage system. Examples include toilets, sinks, bathtubs, shower receptors, and water closet bowls. The term is used erroneously in common vernacular to describe fittings. (See "Fittings.")

Gallons per minute (GPM or gpm)

A measure of the rate at which water flows through a fixture or fitting at a certain pressure. It is measured by the number of gallons flowing from the device in one minute at a given water supply pressure.

Gallons per flush (GPF or gpf)

A measure of the total volume of water required to flush a water closet or urinal, measured in gallons.


While sometimes used by the general public to mean a bathroom or washroom, the plumbing industry uses lavatory to mean a bathroom washbowl or basin permanently installed with running water. The plumbing industry uses the term "sink" in reference to kitchen sinks.

Performance-based product standards

These standards define a desired outcome from products, related to what they do, rather than how they are made and what they are made of. These standards typically prescribe a means for determining whether the product delivers to the standard. For example, a performance-based product standard for fittings would specify the maximum amount of alloy materials, such as lead, that may be leached into the drinking water.

Porcelain enamel

A coating used on metal fixtures, such as cast iron sinks and bathtubs. Ceramic material is fired at high temperature to form a vitreous porcelain film that is fused to the base metal of the fixture or fused to a ground coat. Porcelain enamel gives metal plumbing fixtures their colors and desirable glossy surfaces.

Plumbing Manufacturers International (PMI)

A not-for-profit trade association of plumbing products manufacturers. PMI member companies produce most of the nation's plumbing products. Read more.

Product standards

Established by research and consensus, product standards define what products are made of, as well as how they perform. For plumbing products, product standards govern the characteristics, materials, performance and operability, as well as how products need to interact with other plumbing-system elements. For example, a product standard for fittings would define the alloys and the amounts that can be used in their manufacture.

Prescriptive product standards

These standards differ from performance-based product standards in that they attempt to achieve a desired outcome by specifying the characteristics, materials, performance and operability of products. For example, a prescriptive product standard for fittings would specify the maximum amount of alloy material, such as lead, that can come in direct contact with the drinking water.

PVD finishes

PVD stands for Physical Vapor Deposition. This process, which occurs in a vacuum chamber, electrostatically applies extremely thin, but extremely dense coatings of exotic metal alloys onto fittings. The resulting finish is state-of-the-art in durability, scratch-resistance and lasting beauty for faucets. A wide range of finishes with PVD is possible, including chrome, nickel, brass and bronze.


A fitting with a movable part that opens or closes one or more passages and thereby allows a liquid flow to be started, stopped, and regulated. In plumbing, valves are used in faucets and showers, and can be called mixing valves because they control the mix of hot and cold water to achieve desired water temperatures.

Vitreous china

A type of pottery most commonly used for plumbing fixtures, such as toilets. It is a compound of ceramic materials fired at a high temperature to form a nonporous body. Exposed surfaces are coated with a ceramic glaze that fuses to the china when fired and gives vitreous china plumbing fixtures their colors and glossy appearance.

Clean Water


In the case of plumbing systems, leaching refers to the process of dissolving a soluble component out of a constituent material at a wetted surface. Materials commonly leached into drinking water from water distribution systems include copper, lead, and nickel.


One of the basic elements (Pb), lead is a soft metal that has been used in plumbing systems for thousands of years. The word "plumbing" derives from the Latin word for lead, plumbum. Lead has a unique ability to resist pinhole leaks, while being soft enough to form into shapes that deliver water most efficiently. Its softness and malleability were for a long time highly desirable properties for manufacturing everything from pipe to paint. Lead is a neurotoxin that can accumulate in the body in soft tissues, as well as bone.

Lead and Copper Rule (LCR)

A United States Environmental Protection Agency regulation dating back to 1991, LCR requires water systems to monitor drinking water that comes through faucets in homes and buildings. If lead concentrations exceed 15 parts per billion (ppb) or copper concentrations exceed 1.3 parts per million (ppm) in more than 10% of homes and businesses sampled in a regional plumbing system, the system must take actions to control corrosion and leaching. If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health, including the possible replacement of plumbing system piping.


Under section 1417(d) of the Safe Drinking Water Act, "lead free" is defined as being no more than 0.2 percent of materials used in solders, and no more than 8 percent of materials used to manufacture pipe, fittings, and well pumps.

National Primary Drinking Water Regulations (NPDWRs, or primary standards)

Legally enforceable federal standards that apply to public water systems. Primary standards limit the levels of contaminants in drinking water. A 1996 amendment to the Safe Water Drinking Act (SDWA) requires that the United States Environmental Protection Agency establish a list of contaminants every five years that are known or anticipated to occur in public water systems and may require future regulations under the SDWA.


Founded in 1944, NSF International is a not-for-profit, non-governmental organization that develops standards and product certifications in the area of public health and safety.

NSF/ANSI Standard 60

A standard related to chemicals used to treat drinking water. Developed by NSF and conforming to the ANSI voluntary standard, the standard was accepted by the NSF board in 1988 to evaluate products, such as softeners and oxidizers, to assure that usage amounts safeguard the public health and safety.

NSF/ANSI Standard 61

A standard related to products that come in contact with drinking water. Developed by NSF and conforming to the ANSI voluntary standard, the standard was accepted by the NSF board in 1988 to confirm that such products will not contribute excessive levels of contaminants into drinking water. Most U.S. states and many Canadian provinces require products used in municipal water distribution systems and building plumbing systems to comply with Standard 61.

Potable water

Water that is satisfactory for drinking, culinary and domestic purposes.

Proposition 65

Also known colloquially as Prop 65, California's Safe Drinking Water and Toxic Enforcement Act of 1986 requires companies to post notice of chemicals in products that can be released into the environment and have been determined by the state to be a cause of cancer. In early 2008, the list included 775 chemicals. Prop 65 impacts residents in other states when they receive such notices in purchased products, such as bathroom faucets. Companies will often post the notification on all products, rather than incur extra costs to isolate products sold only in California.

Safe Drinking Water Act (SDWA)

The Safe Drinking Water Act (SDWA) is a federal law originally passed by Congress in 1974 to protect public health by regulating the nation's public drinking water supply. Amendments were passed in 1986 and in 1996. The SDWA requires many actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and ground water wells. SDWA authorizes the United States Environmental Protection Agency to set national health-based standards for drinking water to protect against both naturally occurring and man-made contaminants. Enforcement is accomplished through the National Primary Drinking Water Regulations.

Water Efficiency


A high-efficiency toilet that gives users the choice of flushing with the maximum amount of water allowed by law (1.6 gpf in the United States) or less water. The average amount of water used by the toilet cannot be more than 20 percent less than the maximum allowable, qualifying it to be considered high-efficiency and eligible for WaterSense labeling.

Energy Policy Act of 1992

Among the provisions of this federal legislation, the Energy Policy Act of 1992 (EPAct ’92) required that all residential toilets had to flush using no more than 1.6 gallons per flush.


The moveable part of a toilet flush valve that releases the water from the tank into the bowl when the toilet is flushed and seals the valve shut when the toilet is not being flushed. The most familiar version is a red replacement rubber ring that can deteriorate over time, leading to leaks and water waste. Newer flapper technologies are impervious to deterioration, increasing water efficiency and reducing operating costs.

Flush valve

Located at the bottom of a toilet tank, the flush valve discharges the water from the tank into the bowl when the toilet is flushed.

Gravity-fed toilets

The most common type of toilet in the United States, gravity-fed toilets rely on the force of gravity to flush the toilet effectively. The natural force of water dropping down from the tank scours the bowl clean and forces water and waste quickly into the trapway.

High efficiency toilet (HET)

A toilet with an average water consumption of 1.28 gallons per flush or 4.8 liters per flush, when tested in accordance with a standard or product specification, such as the United States Environmental Protection Agency's WaterSense program. HETs use 20 percent less water than mandated by the Energy Policy Act of 1992, which lowers utility bills and reduces the strain on septic systems. HETs are eligible for special rebates in many drought-prone areas. They are available as single flush gravity toilets, dual-flush gravity toilets or pressure-assisted toilets.

High efficiency urinal (HEU)

A urinal that uses a half gallon or less of water, half the amount allowed under the by the Energy Policy Act of 1992, Contributes to lower utility bills, while reducing the burden on septic systems. HEUs are sometimes thought to be waterless, which isn't true. Waterless urinals are one type of HEU, but there are also urinals that use water and still meet higher efficiency standards.


In the plumbing industry, low-flow fixtures and fittings refer to plumbing products that meet the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term "low consumption."

MaP Testing

A voluntary test protocol for toilets that measures the ability to remove solid waste, also referred to as "bulk." Cooperatively developed in 2003 by water utilities and water-efficiency specialists in the United States and Canada, it uses soybean paste (miso) as test media, in an effort to replicate "real world" waste. The test is conducted by successively increasing the amount of test media that is flushed until the toilet is no longer able to reliably or completely remove the media from the bowl. Results are reported as a MaP score, which is related to the number of grams of a test media that a toilet can adequately flush.

Metered toilets, or metered flush

A toilet with a mechanism that delivers a precise, non-variable amount of water with each flush.

Pressure-assisted toilets

A toilet that uses a compressed-air device to enhance the force of gravity used to clean the bowl when the toilet is flushed.


The channel in a toilet that connects the bowl to the waste outlet. The trapway is measured in terms of the largest diameter ball that can pass through it, called a ball-pass or ball-passage.


In the plumbing industry, ultra-low flow fixtures and fittings refer to plumbing products that exceed the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term "high efficiency"


WaterSense is a partnership program sponsored by United States Environmental Protection Agency, which works to promote water efficiency and enhance the market for water-efficient products, programs, and practices. Similar to the EnergyStar program that helps consumers choose energy-efficient appliances, WaterSense helps consumers to choose water-efficient products by specifying the maximum flow rates and minimum performance levels. Products certified as meeting current WaterSense product specifications are eligible to carry the WaterSense label.

Health & Safety

Accessible design

An approach to designing buildings, homes and products that renders them easier to access and use by people with physical, sensory, or cognitive disabilities.

ADA-compliant device

A device which is fully compliant, when properly installed, with the current requirements of the Americans with Disabilities Act Accessibility Guidelines (ADAAG), as legislated by the Americans with Disabilities Act of 1990.

Americans with Disabilities Act (ADA)

A federal law, passed in 1990, which prohibits discrimination against people with disabilities. The term "disability" means a physical or mental impairment that substantially limits one or more of the major life activities of such individuals. Among the provisions in the law are requirements that impact plumbing products in the design of accessible bathrooms and facilities.

Automatic compensating valve

A valve that is supplied with hot and cold water, and provides a means of automatically maintaining the water temperature selected for an outlet. Automatic compensating valves are used to reduce the risk of scalding and thermal shock.


A flowing back or reversal of the normal direction of wastewater from homes and buildings, leading to the possible contamination of potable water systems.

Backflow prevention device

Any mechanical device designed to automatically prevent backflow.


Products and buildings are considered "barrier-free" if they permit access by all users, including those in wheelchairs. In plumbing products, the term can refer to showers that do not have a lip preventing wheelchair access, as well as sinks and water fountains that are useable at different heights.

Pressure-balancing valve

Also known as a pressure-compensating valve, this device is designed to reduce the risk of thermal shock and scalding while showering. Required by code in most areas of the United States, a pressure-balance valve senses the hot and cold water pressures coming in from the supply line and compensates for variations to maintain the water temperature. Such variations can occur when a toilet is flushed or a washing machine started while someone is showering.

Proximity valves

An electronic valve for plumbing fixtures and fittings that enables them to be operated without being touched. Similar to auto-open doors and light sensors that are activated by movement, proximity valves deliver the benefits of being both barrier-free and sanitary to use. Proximity valves can operate toilets, urinals and faucets.

Thermostatic valves

Also known as a thermostatic compensating valve, this technology senses the temperature of the water to adjust the mix of hot and cold water. This maintains a safe, comfortable water temperature whether the fluctuation is due to a change in the pressure or the temperature of the incoming hot and cold water supplies.

Thermal shock

A large and rapid change in the water temperature. Thermal shock is a particular concern for showers where rapid changes in the temperature of the water can lead to scalding, as well as increased risk of injuries due to slips and falls. Technologies to prevent thermal shock include pressure-balance and thermostatic shower valves.

Universal design

Universal design should be accessibility that is not apparent and, at the same time, can accommodate a wide variety of people of all ages and statures. It allows access to a richer life by eliminating disability by design. This thoughtful approach to space and barriers allows the maximum number of people to use the widest variety of products in their homes for the greatest length of time.