When a water main must be laid under a sewer main, the sewer pipe must be:

When a water main must be laid under a sewer main, the sewer pipe must be replaced with a water-type pipe that has pressure-tight joints. This requirement is primarily due to the need to prevent potential contamination of the water supply from the sewer system. Water-type pipes are designed to handle the pressure associated with water mains and help ensure a safe drinking water supply, while also providing adequate separation between the two utilities.

Using pressure-tight joints is crucial because it minimizes the risk of leakage, which could lead to cross-contamination. If the sewer pipe were to leak, it could introduce contaminants into the drinking water system, compromising public health. This is why adherence to specific standards and regulations is critical when installing these utilities in close proximity, ensuring that the integrity of the water supply is maintained.

In contrast, the other options do not provide the necessary level of protection or risk mitigation. For example, lining the sewer pipe with epoxy addresses deterioration but does not offer the same level of assurance against leakage and contamination as pressure-tight joints in a water-type pipe. Cleaning the sewer pipe may be important for maintenance but does not change its structural integrity or function in relation to the water main. Removing the sewer pipe during installation could be impractical and disruptive, particularly in established areas