Protect Your Drinking Water: Understanding Cross-Connections
At California Water Service, we work hard to confirm that the water we deliver to you meets or surpasses all drinking water regulatory standards. Our Cross-Connection Control Program is one of many critical tools we use to maintain the safety of drinking water throughout the water system all the way to the plumbing at your property. This program is a partnership between Cal Water and our customers. Your understanding of cross-connections and what you can do to protect against them prevents contamination of the drinking water supply, keeping it safe for you and the community.
¿Qué es una conexión cruzada?
Cross-connections are points in the water system where non-potable water sources-which are unsafe for drinking-on your property could contact drinking water. Algunos ejemplos de fuentes de agua no potable son el agua de lavado de un balde, las piscinas, los sistemas de riego de jardines, los rociadores de pesticidas y fertilizantes, las bombas reforzadoras y otros aparatos y equipos que usan agua. Normally, drinking water flows one way into your property; however, unprotected cross-connections could allow contaminated water from non-potable sources on your property to backflow-or reverse flow-into the drinking water distribution system, impacting water quality and posing a risk to both the drinking water system and public health. A public water main is a pipe that delivers drinking water to your neighborhood. Privately owned water service laterals downstream of your water meter are pipes that connect the main to your property.
Where are cross-connections typically found?
Cross-connections can be found throughout residential and commercial plumbing systems. Here are examples of where you can look for cross-connections between the drinking water system and non-potable sources on your property:
- Hose bibbs
- Toilet flush valves
- Swimming pool fill lines
- Space heating boilers
- Recirculation or booster pumps
- Landscape irrigation systems
- Fire sprinkler systems
- Secondary source of water such as a private well or pond
You can also create temporary cross-connections when you submerge hoses, for example a bucket full of wash-water, or when you connect a chemical sprayer to a hose.
Why should I be concerned about cross-connections?
Cross-connections can introduce harmful contaminants into the drinking water supply, leading to public health risks. Examples of contaminants and hazards that could enter your drinking water system without proper cross-connection control include:
Biological Contaminants:
- Harmful pathogens
- Biological substances, such as blood and fecal matter
Chemical Contaminants:
- Household cleaning products such as bleach and detergents
- Pesticides and herbicides used for pest and weed control
- Fertilizers
- Antifreeze and corrosion inhibitors used in heating and cooling systems
- Heavy metals such as chromium or lead used in industrial processes
If they make their way into the drinking water system, these contaminants degrade water quality and can cause serious illness.
How can cross-connections cause contamination?
To maintain a high-quality drinking water supply, water delivered to your property is intended to flow only in one direction. However, unprotected cross-connections could allow contaminated water from non-potable sources on your property to backflow-or reverse flow-into your drinking water system. Backflow degrades your property's water quality and poses a risk to the larger drinking water system and public health. Backflows can occur at unprotected cross-connections due to pressure differences.
Backflow can occur in two ways:
- Backpressure: When the pressure in a non-potable water source (such as a boiler) is greater than the pressure in the drinking water system, contaminants from the non-potable water source can be pushed into your drinking water. Buildings four or more stories high with booster pumps may generate backpressure.
- Backsiphonage: When there is a sudden drop in drinking water system pressure, such as during firefighting or a water main break, a vacuum or siphoning effect can draw non-potable water and any contaminants present into your drinking water.
Examples of backflow conditions at cross-connections due to pressure differences.
How do I prevent contamination at cross-connections?
An air gap, which is an approved vertical separation between a drinking water faucet or pipeline and the highest fill level of a receiving container, can protect against backflow at cross-connections. There are also several types of backflow prevention assemblies that are approved for cross-connection control. These assemblies are specifically designed to prevent reverse flow into the drinking water system when pressure changes occur.
There are other plumbing fixtures that are used at cross-connections, such as hose bib vacuum breakers and irrigation anti-siphon control valves, which are commonly sold in home improvement stores. These items can be installed on your property (for example, at hose bibbs)to protect water quality within your property; however, only approved and testable backflow prevention assemblies may be installed at your water meter to safeguard the public side of the drinking water system.
For more information on approved cross-connection control, contact our local Cross-Connection Control Program Manager.
What are the cross-connection control requirements for property owners?
Property owners are responsible for confirming that air gaps and backflow prevention assemblies on the owner's side of the water meter, where required, are properly installed and maintained on the property.
Air gaps must be inspected annually. Backflow prevention assemblies must be inspected and tested annually by certified backflow prevention assembly testers. This helps to confirm that airgaps and assemblies are functioning properly and continue to protect the drinking water system.
Failure to comply with these requirements could result in discontinuation of water service until proper cross-connection protection is in place. We will notify you if backflow survey results indicate that your property needs backflow protection.
What are steps I can take to prevent backflow?
Don't:
- Submerge hoses in pools, buckets, or other containers.
- Attach chemical dispensers, like pesticide sprayers, to hoses.
- Connect your drinking water plumbing to an appliance without proper education on plumbing codes and any potential risks.
Do:
- Keep hoses stored safely and clear of contaminants.
- Inspect your plumbing for potential unprotected cross-connections.
- Use air gaps or approved backflow prevention assemblies to protect against backflow, and schedule inspection/testing when required.
- Contact us if you notice changes in your water quality or suspect contamination of your drinking water. Your local Cross-Connection Control Program Manager's contact information is listed at the link below.
Keep Your Drinking Water Safe: A Shared Responsibility
The State Water Resources Control Board has new requirements for public water agencies to provide more information on cross-connections to the public. Together, we can keep drinking water flowing one way into your property, keeping it safe for you and the community.
Content courtesy of California Urban Water Agencies
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