The answer to 'why is my pipe constantly running' is that there is likely a problem with the plumbing system that is causing water to continuously flow through the pipes. This can be caused by a leaky faucet, a malfunctioning toilet, or a problem with the main water line. A constantly running pipe can waste a significant amount of water and lead to higher utility bills.
Some common symptoms of a constantly running pipe include the sound of running water even when no fixtures are in use, a spike in water usage, and water pooling around the pipe or fixture. To diagnose the issue, you'll need to inspect the plumbing system and identify the source of the leak or problem.