Overview

Your local water provider is responsible for ensuring the water delivered to your home is safe for everyone to drink. However, certain hydraulic conditions left unprotected within your plumbing system may allow hazardous substances to contaminate your own drinking water or even the public water supply.

A cross-connection is an actual or potential connection between the safe drinking water (potable) supply and a source of contamination or pollution. State plumbing codes require approved backflow prevention methods to be installed at every point of potable water connection and use. Cross-connections must be properly protected or eliminated.

 

Examples of Residential Cross-Connection Hazards

 

State regulatory agencies require all public water suppliers to maintain an on-going Cross-Connection Control program involving public education, onsite inspections/surveys, and possible corrective actions by building and home owners if required.

Terminology

Water normally flows in one direction. However, under certain conditions, water can actually flow backwards; this is known as backflow. There are two situations that can cause water to flow backward: backsiphonage and backpressure.

 

Backsiphongage - this may occur due to a loss of pressure in the public water system from a fire fighting emergency, water main break or system repair. This loss of pressure creates a siphon effect in the plumbing system which can draw water out of a sink, bucket, or pool and back into your water or public water system.

Backpressure - may be created when a source of pressure in your home plumbing system (such as a boiler or pump) creates a pressure greater than the water pressure supplied through the public water system. This may cause contaminated water to be pushed into your plumbing system through an unprotected cross-connection.


PART I: INSPECTIONS / SURVEYS

PART II: BACKFLOW PREVENTION ASSEMBLY TESTING

PART III: GENERAL RESOURCES

SAMPLE BACKFLOW PREVENTION DEVICES AND ASSEMBLIES:

Hose connection vacuum breakers:

Example: Hose connection
vacuum breakers

 

Example: Integrated vacuum breaker
on outside hose spigot.

Avoid these cross-connection hazards:

Example: Hose end in bucket

 

Example: Hose end in pool

Incorrect continuous pressure installations:

 

Vacuum breaker should not be subject to continuous pressure like the example here illustrates. (This type of irrigation set up/system would need to be corrected.)

EXAMPLES OF BACKFLOW PREVENTION ASSEMBLIES:

These require periodic performance testing by a Certified Tester.

Pressure Vacuum Breaker Assembly

 

Reduced Pressure Principle
Backflow Prevention Assembly