Water Heater Temperature Setting
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Thermostat setting at the tank. Aging skin is thinner and reacts more slowly, so the safety margin is smaller.
Widely recommended by burn-prevention programmes; also the usual anti-scald design point.
At 140°F — a common factory setting — a serious burn takes about five seconds. At 120°F it takes several minutes. That gap is entirely reaction time, and reaction time is exactly what is reduced in the people this site is about.
Two places to control it
- At the tank. Simple, free, affects the whole house. Gas heaters have a dial; electric usually needs a panel removed and the power off.
- At the fixture. A thermostatic anti-scald valve at the shower or basin holds a set temperature even if someone flushes a toilet. Better protection, but a plumbing job.
Turning the tank much below 120°F can let bacteria grow in stored water. 120 is the balance point, not a floor to keep lowering.
Check it with a thermometer, not a hand
Run the hot tap for two minutes, fill a cup, measure. Dial markings on water heaters are frequently wrong by ten degrees or more.