A cross-connection is any connection between your home's
plumbing system and any source of water that is not fit for
consumption. An example of such a cross connection is a
home irrigation system that is connected to your plumbing
system without a proper backflow prevention assembly. Otherwise,
contaminated water from your irrigation system may flow back
into your household plumbing if a major water pipe should break.
Local building departments enforce the plumbing codes that ensure
that household plumbing systems, including irrigation systems, are
designed and installed to prevent cross-connections. The
building department will inform you of the proper steps that needs
to be taken, and of the permits and inspections that will be required.