Backflow and its dangers
As your drinking water supplier, we are concerned
about the possible introduction of contaminants to the
drinking water from our users. Most outside
contamination takes place when the customer uses
equipment that re-pressurizes the water supplied, or
when negative pressures occur in the water supply mains,
as with a water main that breaks.
Like most water suppliers, the District closely
monitors commercial and industrial customers for
backflow problems. We often require special
testable devices placed in these customers' water supply
piping to prevent such contamination.
Residential customers can also cause contamination.
Permanent irrigation systems require the installation of
a backflow prevention device. Lawns are typically
treated with composted materials and/or chemical
fertilizers. In the event of a flow reversal,
these contaminants could be introduced into the
household or the water distribution system.
Another potential source of contamination are the
newer aspirator devices that are sold to apply
insecticides and fertilizers. Though they are
often equipped with a check valve, they are easily
fouled and often fail. Vacuum breakers are the
best protection in this situation and can be purchased
at most hardware stores. Many new outside sill
(outside faucets) have built-in vacuum breakers.
Never leave aspirator devices connected to your water
supply when not in use.