A plumbing cross-connection is when a direct link between
drinking water and sewage water exists in the homes plumbing
lines. This situation exists an many homes and is all too
common. The most common scenario for a cross-connection
to be present is when a house has a water softener. Water
softeners have a discharge tube to extract water when the
systems cycles itself. That hose should run into a sink
or sump-pump crack. Many times the discharge tube is attached
directly into a sewer drain line causing a cross-connection.
(See Above Photo) Other common cross-connections exist that
are not as noticeable. A faucet spout that extends below
the rim of the sink is another common cross-connection.
If the sink fills up all the way and the faucet spout becomes
submersed, a cross-connection has occurred.
Dangers Of Cross-Connections
What makes a cross-connection so dangerous? If water pressure
to the house were to drop suddenly, a siphoning situation
would occur and actually pull sewage from the drain lines
into the water supply lines and contaminate drinking water.
This can happen weather the house is on a well or municipal
water on a septic system or town sewers.
Drop In Water Pressure
Water pressure may drop causing this to occur for any number
of reasons. From time to time municipal water authorities
flush the water lines on streets and fire departments may
use the lines nearby. This causes a dramatic loss of water
pressure causing dangerous conditions if a cross-connection
exists. Also a malfunctioning well pump may cause siphoning
of the lines to exist.