distribution systems are designed with the intention of the water flowing
in a certain direction, from the distribution system to the customer.
However, hydraulic condition within the system may deviate from the "normal"
conditions, causing water to flow in the opposite direction. Therefore,
it is possible for the water to flow in the opposite direction in unprotected
systems. This is called backflow.
Backflow is caused by mainline piping failures or drafting due to high
demands. For example, it is a condition that can occur when the drinking
water system pressure drops below that of the fire protection system,
drawing the fire protection system water back into the drinking water
system. Another instance is while using a pesticide attachment on the
garden hose, the pesticide may be siphoned back up the hose and into your
pipes if the water pressure suddenly drops. As a result, bacteria, chemicals
and poisons can contaminate your drinking water.
· Inground lawn sprinklers
· Inground swimming pools
· Hose Bibbs
· Photo Dark Rooms
· Solar Heating
· Decorative Ponds
· Fire Protection Systems
Cross-connection is an unprotected actual or potential connection between
a potable water system used to supply water for drinking purposes and
any source or system containing unapproved water or a substance that is
not or cannot be approved as safe, wholesome, and potable. By-pass arrangements,
jumper connections, removable sections, swivel or changeover devices,
or other devices through which backflow could occur, are considered to
If you have domestic water service, an irrigation system, or a fire protection
system, you probably have backflow devices already present on your property.
Your local water authority requires that these devices be tested on a
regular basis. Failure to comply with testing requirements may result
in fines and your water service being discontinued. Due to recent developments
regarding water contaminations and the war on terror, compliance is mandatory.
Backflow prevention devices are mechanical plumbing devices (valves) installed
in a plumbing system to prevent water from flowing backwards and causing
drinking water contamination. A properly installed, tested, and maintained
backflow device at the service entrance to the building or property can
reliably prevent dangerous backflow contamination of drinking water.