Cross connections are common in modern construction. They are present in the water distribution systems we use every day in our homes, at work, where we shop and where we play.
Examples of a cross connection:
- Appliances such as washing machines, dishwashers, water softeners
- Lawn irrigation systems
- Mechanical equipment such as boilers, chillers and chemical dispensers
- Fire sprinkler systems
Cross-connections are most prevalent in:
- Grocery stores
- Automotive repair and maintenance facilities
- Buildings with fire sprinkler systems
- Health care facilities
- Health Clubs
- Swimming pools
- Sports fields (with irrigation system)
- Manufacturing facilities
The water supply system is under constant pressure to be able to deliver water from its source to points at higher elevations or even the top floor of a high rise. Most of the pressure is created by pumps. A potential for backflow occurs in a plumbing system when the supply pressure is reduced or interrupted.
A backflow event can occur for many reasons:
- Pump failure
- Damage or maintenance of supply lines
- Electrical failure or power outage
- Heavy localized water use (i.e., fire-fighting)
A backflow event cannot be predicted, and because our water pressure relies primarily on mechanical pumps, the potential for backflow is always present. However, backflow can be isolated, minimized, controlled or prevented by use of backflow prevention assemblies, devices, and methods.