Where are combination stop-and-waste valves not allowed to be installed?

Combination stop-and-waste valves are designed to provide a convenient means of controlling water flow and facilitating the drainage of water lines. However, these valves are generally not allowed to be installed underground due to several important considerations.

When installed underground, there is a risk of water accumulation, which could cause the valve to malfunction or become damaged over time due to soil conditions, moisture, or debris. Additionally, underground installations can make it difficult to access the valve for maintenance or repairs, potentially leading to costly problems if the valve needs servicing. Local plumbing codes typically emphasize the importance of accessibility for maintenance purposes, and requiring that valves be above ground or in easily reachable locations is a common rule to promote proper function and safety.

By prohibiting underground installations, codes ensure that the valves remain accessible for routine inspections and maintenance while reducing the risk of water-related issues that could arise from improper drainage or valve failure. This focus on accessibility and functionality ultimately supports the long-term performance and reliability of plumbing systems.