Smooth glass electric cooktop built into a wooden counter
Generic photo: Max Vakhtbovych · Pexels License

Hot water looks cloudy or milky

Most milky hot water is dissolved air coming out of solution as the water heats; it is harmless and clears in a minute or so. A simple glass test tells you: if it clears from the bottom up, it is air. If it stays hazy, settles particles or has a color or odor, look at hardness minerals, sediment in the tank, a failing dip tube, or rust.

Single source ~20 min easyBrands: All

Before you start

  • Hot water can scald when flushing the tank
  • Electric heater: breaker off before draining. Gas heater: control to pilot/vacation; no work on the gas valve or burner

Diagnostic steps

Unlock all 4 steps with expected values

Full library + AI assistant + the OnCall Tech app for iPhone & Android. $34.90, one time.

Get lifetime access

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

More water heaters guides

Guide · Water Heater

Heat-pump (hybrid) water heater: slow recovery, noise, errors

Hybrids need enough room air and a clean air filter, a working condensate drain and the right mode. Many complaints are mode settings or a dirty filter. Refrigerant faults are sealed-system work.

5 steps ~60 minmoderate
Guide · Water Heater

Tankless water heater descaling (flush)

Scale insulates the heat exchanger, causing overheat codes and fluctuating temperature. Flush with a pump and descaling solution through the isolation valves.

5 steps ~75 mineasy
Guide · Water Heater

Hot water recirculation pump problems

Check timer/settings, check valves, air in the loop and the pump itself. On tankless units with built-in pumps, a recirculation code may point to air or a leak in the loop.

5 steps ~60 minmoderate
Hot water looks cloudy or milky · OnCall Tech