Can Cross-Connection Be Hazardous?
Yes, in the old days many disease epidemics were caused by cross-connections between potable water systems and raw river water or lake water piping systems. Epidemics of typhoid and cholera were often caused by backflow occurrences from these sources and people died or were very ill. A few of the contaminants caused by cross-connections are:
Bacteria cultures from laboratories
Boiler water with chemicals
Blood and body fluids from funeral homes
Heavy metals (such as arsenic)
Pesticides, herbicides, and fungicides
Untreated river, sea, or lake water
Water from carwashes
Water from flush toilets
Worm treatment for poultry
This is only a partial list of documented cases of potable water contamination by virtue of cross-connections and backflow occurrences. These cases still happen everyday.