Shower problems are uniquely annoying — temperature swings, weak flow, drips that echo at 3 AM. Most trace to the shower valve cartridge ($30–$80 part, 30-minute fix); full valve replacement runs $300–$800+ installed. This section covers cartridge diagnosis and replacement, what shower valve replacement involves (including when tile has to come out), and tub drain plumbing basics.
Cartridge first, always
Temperature fluctuation, drips from the showerhead, and stiff handles are cartridge symptoms in the large majority of cases. Shut off water, pull the cartridge, match it at the store — our guide covers the stuck-cartridge tricks.
When the wall has to open
A leaking valve body (not cartridge), switching valve types, or moving the shower location means opening the wall. Our replacement guide explains access-panel strategy so the tile damage stays minimal and repairable.