Dripping only on hot side

Quick Answer:

If your shower only drips after you run hot water, that usually means the hot side of the valve isn’t sealing properly or hot water is continuing to reach the outlet after you shut it off. A quick test—run cold-only, shut off and note the drip, then run hot-only and compare—will tell you whether the problem is limited to the hot side.

Why This Happens

Most modern shower valves have separate seals or a mixing cartridge that controls hot and cold flow. If the hot-side seat, cartridge sealing surface, or a pressure-balancing component is worn or damaged, hot water can leak past when the handle is off. Heat also causes parts to expand slightly, so a seal that looks fine with cold water can leak once it heats up. If the issue started right after work was done on the plumbing, consider that the valve or cartridge may not have been seated correctly—see Dripping started after plumbing repair.

Step-by-Step What to Do

1. Do a simple cold-only then hot-only test

• Turn the shower to cold-only and run for 10–20 seconds, then turn it fully off.
• Watch for any dripping and note how quickly or heavily it drips.
• Repeat the same procedure with hot-only water.
• Compare results: if cold shows little or no drip but hot produces a consistent drip, the problem is on the hot side of the valve or mixing cartridge.

2. Inspect visible parts

• Check the showerhead and hose for mineral buildup or loose fittings—sometimes the drip is reduced or stopped by tightening the connection, but this is only a temporary fix if the valve is leaking.
• Look for obvious signs of water on the face of the trim or around the handle that appear after running hot water.

3. Check for related behaviors

• Note whether dripping continues for a long time after the water is shut off; prolonged dripping can signal thermal expansion or a bad seal—compare with information about Shower drips for hours after use.
• If the drip started after replacing a showerhead, cartridge, or doing other plumbing work, that timing is a clue.

4. Decide on a repair approach

• If the valve is several decades old, replacing the cartridge or valve can be the long-term fix.
• If you’re comfortable, you can remove the trim and inspect the cartridge for wear or debris; if it’s corroded or the seats are worn, replacement is usually needed.
• If you aren’t comfortable working on valves or the valve is behind a finished wall, call a professional.

What Not to Do

• Don’t crank the handle tighter than normal to stop a hot-side drip—this can damage the valve or strip internal parts.
• Don’t ignore a persistent hot-only leak; if hot-only persists after the tests and simple checks, a plumber is appropriate rather than continued DIY attempts that could make the problem worse.

When to Call a Professional

• If the hot-only drip continues after you confirm the issue with the cold/hot test.
• If the cartridge or valve must be replaced and the valve is behind a finished wall or you don’t have the right parts or tools.
• If you notice water damage, reduced water pressure, or the leak affects other fixtures.

Safety Notes

• Hot water can cause scalding. When testing, set your thermostat to a safe level and avoid prolonged exposure to hot spray.
• Shutting off the home’s main water is sometimes necessary for valve work—only do that if you know how, or have a professional do it.
• Working on plumbing behind finished walls can risk water damage; if you’re unsure, stop and call a plumber.

Common Homeowner Questions

• Why does it only drip after I run hot water? Heat can expand worn seals or open a gap in the hot-side seat or cartridge, allowing hot water to leak after shutoff.
• Can I fix it by replacing the showerhead? Unlikely—if the drip is from the valve, replacing the head won’t stop a hot-side valve leak.
• Will letting hot water run for a while stop the drip? No. Running hot water may make the leak more apparent; it doesn’t repair a worn seal or cartridge.