Cross-connections can be found in both residential and commercial plumbing systems. Here are examples of where you can look for cross-connections between your drinking water system and non-potable sources on your property: hose bibbs, toilet flush valves, swimming pool fill lines, space heating boilers, landscape irrigation systems, recirculation or booster pumps, and fire sprinkler systems. If you have another source of water to your property, such as a well or pond, that may also be a source of a cross-connection.