5 Incidents of Backflow Due to Cross-connections

5 Incidents of Backflow Due to Cross-connections

September 13, 2021 Off By idswater

Sometimes contaminants can be introduced into the distribution system and pollute your drinking water. This problem usually occurs due to connections between potable water lines and non-potable water sources and cross-connections, something we call cross-connections. While cross-connections are unintentional. They become the point at which. It is possible for a non-potable substance to come in contact with the drinking water system. To help you understand how backflow incidents can contaminate drinking water, here are a few real incidents. Where inadvertent cross-connections led to possible back-flow.

Fire Fighting system

When customers at a nationally renowned fast-food restaurant in Virginia started to complain about a saltish taste in all beverages served at the restaurants, investigations were made. As it turned out, the restaurant was served from the main distribution line where the issue originated. A nearby waterfront ship repair facility housed. A fire protection system with high-powered pumps to maintain high pressure of sea water in the fire-service lines. A loss of pressure created a vacuum, causing the stagnant sea water in the firefighting system to enter into the public water distribution system. Upon a cross-connection control inspection of the supply line, it was found that the backflow preventer valve installed on the service line to the restaurant had malfunctioned, thereby proving defenseless against backflow.

HVAC System

Hundreds felt sick at a medical facility in Colorado Springs after drinking water that tasted and smelled odd. Similarly, students at an elementary school suffered nausea and other symptoms after a malfunction at the HVAC system caused the antifreeze chemical glycol to backflow into the school’s drinking supply. The investigations revealed a faulty connection between the drinking water and the HVAC system. Which caused water containing Propylene glycol to leak into the main supply line due to backflow. Malfunctioning cross connections always lead to backflow whenever there is a change in water pressure or a disruption to the water line, compounded by lack of protection. Propylene glycol is highly dangerous for human health and its consumption made people severely ill. To keep the drinking water safe, backflow preventer should be installe on the HVAC system lines. Also always purchase the backflow preventer valve or any other plumbing things from any best renowned plumbing manufactures so that you never face any difficulties.

Sprinkler System

When a North Carolina clinic complaine of bitter taste and a strong chemical odor in the water supply. The authorities came to investigate the matter. As it turn out. The garden hose that was use to fill the clinic’s x-ray development chemical mixer with water, was connecte to a hosebibb that did not have a vacuum breaker valve in place. The garden hose would be fully submerg in the chemical mixer without any protection in place. Which resulte in an impromptu cross-connection. The negative pressure in the hose pipe cause the chemicals in the X-ray developer to be back-siphon through the garden hose and enter the portable water supply. As a result. The water supply to the clinic was contaminat and the water had to be treat. Before it could be portable again.

Swimming Pool

After two children fell ill with bacteriological infections, professionals were call in to test the quality of water at their home. When ask to describe the characteristics of water, the mother report that the water receive at home smell like algae. As it turn out. The mother had fill the pool with a garden hose by immersing the hose in the pool and notice it siphoning water. Another reason was that the household didn’t regularly operate their chlorination system, due to which it nurtur algae. The problem with this cross-connection contaminate the entire water distribution.

Herbicide tank

Residents in a small town in Maryland complain of a yellow gushy stuff pouring out from some faucets. Upon investigation, it  reveal that due to low water pressure in the distribution system. A temporary vacuum was create, due to which water from an herbicide chemical holding tank seep into the town water supply mains. Later when the water pressure  normalize, this water was pump into houses. There wouldn’t have a cross-connection if the gate valve between the two water supplies had  properly shut off. Since the water was contaminate with harmful chemicals, residents were warn not to use that water for cooking, drinking, bathing or any other purpose.


For further reading: skooknewsmagazine.com