The answer to 'shower constantly running' is that the most common causes are a faulty shower valve, a problem with the shower cartridge, or a clogged shower head. Symptoms include water continuously dripping or flowing from the shower head even when the water is turned off. Solutions can range from a simple DIY shower head cleaning to a more complex shower valve replacement that may require a professional plumber.
If the shower is constantly running, the first step is to check the shower head for any debris or mineral buildup that could be causing a blockage. You can try cleaning the shower head with a vinegar solution or replacing it entirely. If the problem persists, the issue may be with the shower valve or cartridge, which controls the water flow. Replacing these components often requires more advanced plumbing skills and tools, so it's generally best to call a professional plumber unless you have significant plumbing experience.