Minimization of cross-connections and backflow prevention are important
safeguards for protecting our drinking water system from accidental
pollution. Cross-connections occur when ever a potable water pipe is
directly or indirectly connected to a piece of equipment, piping, or
container of non-potable water or other liquid. Backflow is the flow
non-potable water or other liquid into a potable water pipe through a
cross-connection. Read more about cross-connections, backflow, and your
role in protecting drinking water here.
Wide Range of Pollutants
Backflow through a
cross-connection can introduce a wide range of pollutants into your home
drinking water pipes, and in some cases, into the community drinking
water system. In May 2014, our customers received a notice in the mail
that the City’s drinking water system had violated the State maximum
contaminant level for Total Coliform bacteria. Total Coliform are
naturally in the environment and generally not harmful themselves but
are used as an indicator that other, potentially harmful bacteria may be
present. Whenever we find Total Coliform in a sample we concurrently
test for E. coli, a disease causing bacteria. We did not find E. coli
in any drinking water samples. Corrective action was taken to flush
the Total Coliform bacteria out of the drinking water system and
subsequent testing showed Total Coliform was no longer present in the
drinking water system.
Example of Backflow
During its investigation of this
incident, the City found some evidence to suggest that the source of total Coliform in the distribution system was from a cross-connection.
In this case, it is suspected that a hose connected to a spigot was
submerged in a decorative fish pond while the pond was filling.
Non-potable water from the fish pond may have back-flowed through the
cross-connection and introduced Total Coliform bacteria into the
distribution system. While this incident was not an emergency, it does
highlight the point that we all have a responsibility to protect our
drinking water resources. Please take a moment to learn about
cross-connections and backflow, and to identify and eliminate any
existing cross-connections at your home or business.