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

Combination stop-and-waste valves are designed to allow for the draining of water systems, making them beneficial in various plumbing applications. However, their installation is not permitted underground due to several crucial reasons.

Installing these valves underground can lead to potential issues such as water accumulation, which can result in damage to the valve and other components of the plumbing system. Additionally, when installed underground, the valve becomes difficult to access for maintenance or repair, increasing the risk of costly repairs or replacements.

Furthermore, underground installations may expose the valve to soil pressure, which can affect its functionality and integrity over time. This leads to the potential for leaks or failures that can compromise the entire plumbing system.

Ultimately, the restriction on underground installations is to ensure safety, accessibility, and proper functioning of the plumbing system, maintaining the integrity and reliability of water service.