Operator terms · Water
What is a cross-connection?
A cross-connection is any point where drinking water can mix with a non-potable source, letting contamination flow back into the clean supply if pressure drops. Backflow prevention, like check valves and air gaps, stops it. Operators guard against cross-connections because they are a direct route for contamination.
Last reviewed 2026-08-03
How contamination gets in
If pressure in the distribution system drops, water can flow backward. Where a cross-connection exists, that backflow can pull non-potable water into the drinking supply.
How it is prevented
Air gaps and backflow-prevention devices such as check valves keep the two apart. Cross-connection control is a core operator responsibility in distribution.
Common questions
- Why is a cross-connection dangerous?
- It is a direct path for contamination to enter drinking water if pressure drops.
- What is backflow?
- Water flowing backward in the system, against its normal direction.
- How is it prevented?
- With air gaps and backflow-prevention devices like check valves.