Shower doesn't get hot enough even at max setting

Symptoms

• Water gets warm but never truly hot
• Problem exists even with the handle turned fully to hot
• Other fixtures may or may not have the same issue
• Water was hotter in the past

Likely causes

• CommonWater heater thermostat set too lowA thermostat below about 120°F will feel noticeably tepid at the shower after mixing.
• CommonAnti-scald rotational limit stop set too conservativelyMany valves have an adjustable stop limiting how far toward hot the handle can turn.
• PossibleSediment buildup in the water heater reducing efficiencyA layer of sediment at the bottom of the tank insulates the burner or element, reducing how hot the water gets.
• PossibleFailing heating element or burner in the water heaterOne of two elements in an electric heater, or the burner in a gas unit, may not be working.

What to do

1. Check hot water temperature at a sink first to see if the problem is house-wide or shower-specific.
2. If house-wide, check the water heater thermostat setting and raise it toward 120°F if it's set lower.
3. For electric heaters, if one tap runs hotter than others, one of the two heating elements may have failed and needs professional testing.
4. For gas heaters, check that the pilot light or ignition is working normally, and note any error codes on newer units.
5. If only the shower is affected, remove the handle and trim to find the rotational limit stop on the cartridge and adjust it toward more heat.
6. Flush the water heater tank to remove sediment if it hasn't been done in over a year, following the manufacturer's drain procedure.
7. Retest at the shower after each change to isolate what improved the temperature.

Tools and parts

• Screwdriver
• Adjustable wrench

When to call a pro

Call a plumber or appliance technician if the water heater itself seems to be the cause, especially for element or gas burner issues.

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