QUESTION: What is a cross-connection?

ANSWER: A cross-connection is any temporary or permanent connection between a public water system or consumer's drinking (potable) water system and any source or system containing non potable water or other substances. An example is the piping between a public water system or consumer's potable water system and an auxiliary water system (underground well), cooling system, heating system or irrigation system.
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QUESTION: What is backflow?

ANSWER: Backflow is the undesirable reversal of flow of non potable water, contaminants or other substances through a cross-connection into the piping of a public water system or consumer's potable water system. There are two types of backflow... backpressure and backsiphonage.
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QUESTION: What is backpressure?

ANSWER: Backpressure is caused by a downstream pressure that is greater than the upstream or supply pressure in a public water system or consumer's potable water system. Backpressure can result from an increase in downstream pressure, a reduction in the potable water supply pressure, or a combination of both. Increases in downstream pressure can be created by pumps, temperature increases in boilers or water heaters etc. Reductions in potable water supply pressure occur whenever the amount of water being used exceeds the amount of water being supplied, such as during water line flushing, fire fighting, or breaks in water mains.
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QUESTION: What is backsiphonage?

ANSWER: Backsiphonage is caused by a negative pressure (i.e., a vacuum or partial vacuum) in a public water system or consumer's potable water system. The effect is similar to drinking water through a straw. Backsiphonage can occur when there is a stoppage of water supply due to nearby fire fighting, a break in a water main, a flow of water on a lower floor in a multi floor building, etc.
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QUESTION: What is a backflow preventer?

ANSWER: A backflow preventer is a means or mechanism to prevent backflow. The basic means of preventing backflow is an air gap, which either eliminates a cross-connection or provides an open gap (physical separation) to prevent backflow. The basic mechanism for preventing backflow is a mechanical backflow preventer, which provides a physical barrier to backflow. The principal types of mechanical backflow preventer are the reduced-pressure principle assembly, the double check valve assembly, pressure vacuum breaker assembly and the standard vacuum breaker (like on residential irrigation systems). A secondary type of mechanical backflow preventer is the residential dual check valve.
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QUESTION: What is a residential dual check valve (RDC)?

ANSWER: A RDC is similar to a DC in that it is a mechanical backflow preventer consisting of two independently acting, spring-loaded check valves. However, it usually does not include shutoff valves, mar or may not be equipped with test cocks or ports, and is generally less reliable than a DC. A RDC is effective against backpressure backflow and backsiphonage but should be used to isolate only non-health hazards and is intended for use only in water service connections to single-family homes.
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QUESTION: What is the new "Lead Free Law" regarding plumbing in California? (Assembly Bill AB 1953)

ANSWER: California Assembly Bill 1953 (AB1953) was signed into law September 30th, 2006 by State Governor Arnold Schwarzenegger. The intent of the bill, which takes effect January 1, 2010, was to reduce the amount of lead in specific plumbing fixtures from its current regulated amount of no more than 8%, to a new standard not to exceed 0.25%. Specific language in the bill states... "No person shall introduce into commerce, for use in California, any pipe, pipe or plumbing fitting, or fixture intended to convey or dispense water for human consumption through drinking water or cooking that is not lead free. This includes kitchen faucets, bathroom faucets, and any other end-use devices intended to convey or dispense water for human consumption through drinking or cooking." (Read the bill in PDF format)
Some states are specifying no-lead materials that contain no more that 0.10% lead.
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QUESTION: Why do backflow preventers have to be tested periodically?

ANSWER: Mechanical backflow preventers have internal seals, springs, and moving parts that are subject to fouling, wear, or fatigue. Also, mechanical backflow preventers and air gaps can be bypassed. Therefore, all backflow preventers have to be tested periodically to ensure that they are functioning properly. A visual check of air gaps is sufficient, but mechanical backflow preventers have to be tested with properly calibrated gauge equipment.
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QUESTION: What are the regulations, requirements and procedures in testing a Backflow Device?

ANSWER: This information may be found in many publications such as; California State Water Resources Board, The Universal Plumbing Code
the USC Foundation for Cross-Connection Control and Hydraulic Research, along with state and local administrative authorities, utilities and water purveyors.
The latest testing procedures can be purchased in the Tenth Edition of the USC Manual of Cross-Connection Control.
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QUESTION: Why do water suppliers need to control cross-connections and protect their public water systems against backflow?

ANSWER: Backflow into a public water system can pollute or contaminate the water in that system (i.e., backflow into a public water system can make the water in that system unusable or unsafe to drink), and each water supplier has a responsibility to provide water that is usable and safe to drink under all foreseeable circumstances. Furthermore, consumers generally have absolute faith that water delivered to them through a public water system is always safe to drink. For these reasons, each water supplier must take reasonable precautions to protect its public water system against backflow.
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QUESTION: What should water suppliers do to control cross-connections and protect their public water systems against backflow?

ANSWER: Water suppliers usually do not have the authority or capability to repeatedly inspect every consumer's premises for cross-connections and backflow protection. Alternatively, each water supplier should ensure that a proper backflow preventer is installed and maintained at the water service connection to each system or premises that poses a significant hazard to the public water system. Generally, this would include the water service connection to each dedicated fire protection system or irrigation piping system and the water service connection to each of the following types of premises: (I ) premises with an auxiliary or reclaimed water system: (2) industrial, medical, laboratory, marine or other facilities where objectionable substances are handled in a way that could cause pollution or contamination of the public water system; (3) premises exempt from the State Plumbing Code and premises where an internal backflow preventer required under the State Plumbing Code is not properly installed or maintained; (4) classified or restricted facilities; and (S) tall buildings. Each water supplier should also ensure that a proper backflow preventer is installed and maintained at each water loading station owned or operated by the water supplier.
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QUESTION: Where can I get more information about cross-connection control?

ANSWER: One excellent reference is the University of Southern California's Foundation for Cross-Connection Control and Hydraulic Research; University of Southern California; KAP-200 University Park MC-2531; Los Angeles, California 90089-2531; 213/740-2032; http://www.usc.edu/dept/fccchr.
Another excellent reference is the American Water Works Association's (AWWA's) Manual M14, Recommended Practice for Backflow Prevention and Cross-Connection Control, which is available from the AWWA Bookstore; 6666 West Quincy Avenue; Denver, Colorado 80235; 800/926-7337; http://www.awwa.org/ .
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