Frequently Asked Questions (FAQs)
What is a cross-connection?
A cross-connection is any temporary or permanent connection between a public water system or consumer's potable (i.e., drinking) water system and a 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, cooling system or irrigation system.
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What is backflow?
Backflow is the reversal of flow of water or other substances through a cross-connection into the public water system or consumer's potable water system. Backflow into a public water system can pollute or contaminate the water in that system making it unsafe to drink. There are two types of backflow . . . backpressure backflow and back-siphonage.
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What is backpressure backflow?
Backpressure backflow is backflow 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.
Causes of increases in downstream pressure: Pumps (such as wells and booster pumps), temperature increases in boilers, etc. Causes of decreases in downstream pressure: Water line flushing, fire fighting, or breaks in water mains.
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What is back-siphonage?
Back-siphonage is backflow 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. Back-siphonage can occur when there is a stoppage of water supply due to a nearby fire fighting, a break in a water main, etc.
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Why does Sacramento Suburban Water District need to control cross-connections and protect its public water system against backflow?
Because backflows can contaminate the drinking water in the public water system, California Code of Regulation, Title 17, requires each Water Supplier to protect the public water supply from contamination by implementing a State approved cross-connection control program. To protect the public health of all of our drinking water customers and to ensure the drinking water quality in our system is safe, Sacramento Suburban Water District has a vigorous Cross-Connection Control Program.
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How does Sacramento Suburban Water District implement the Cross-Connection Control Program?
Sacramento Suburban Water District (District) adopted Regulation 14 on July 19, 2004 (amended in November 17, 2008) which identifies the requirements for the District’s Cross-Connection Control Program (Program). The Program requires all new service connections and certain existing service connections to install an approved backflow prevention device. Examples of some of the existing service connections are listed below, a full list of requirements is listed in Regulation 14.
- Premises with an auxiliary water supply, such as a private well
- Premises with more than one service connection
- All fire services
- All non-residential services which have a water meter installed.
The District has agreed with the California Department of Public Health to retrofit a certain number each year to comply with state requirements. All addresses identified as those which may require installation of a backflow prevention device have been placed on a priority list and installation notices will be issued as time warrants.
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What is a backflow prevention device?
A backflow prevention device is a means or device which prevents pollutants and contaminants from backflowing into the public water system. Approved backflow prevention assemblies.
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What is an air gap?
An airgap is a vertical, physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel. This separation must be at least twice the diameter of the water supply outlet and never less than on inch. An air gap is considered the maximum protection available against backpressure backflow or back-siphonage but is not always practical and can easily be bypassed.
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What is a reduced principle zone assembly (RPZA)?
A reduced principle zone assembly protects water from substances that may contaminate water causing illness or death. A sprinkler/irrigation system that has a chemical feed requires this device. It is also commonly used in commercial establishments to protect against numerous contaminants. These devices must be installed above ground.
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What is a double-check valve assembly (DCVA)?
A double-check valve assembly protects water from substances that may pollute but not contaminate the water. For instance, fire protection systems are often required to be protected by these devices.
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Why do backflow preventers have to be tested annually?
In order to ensure the proper operation of a backflow prevention device, it must be tested and certified upon installation and annually thereafter as required by state code. Laboratory tests on all approved backflow prevention devices indicate that some components may fail in time, and periodic testing is the only method to ensure that the backflow prevention device is functioning properly and protecting the public water system.
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