Cross connection between sanitary and storm water can be identified by?

• A. Reading utility maps
• B. Checking reliable records
• C. Estimating surface drainage
• D. Using dye testing

Answer: (D)

Directly tracing the flow between the two sewer systems is what identifies a cross-connection, and dye testing does that by visibly following colored water. In practice, a non-toxic dye is introduced into one system—often the stormwater or a suspected branch—and observers watch whether the dye shows up in the sanitary sewer or a building drain. If the dye appears where it shouldn’t, it proves there’s a connection between the systems, which is the exact problem a cross-connection test is meant to reveal. This method provides direct, visible evidence of a linkage, unlike maps or records, which may be incomplete or outdated, or surface-drain estimations, which don’t confirm actual plumbing connections.