Diagnose your tap water by symptom
Odd smell, odd color, odd taste? Each page below starts with the one check that narrows it fastest — whether the problem is on the hot tap, the cold tap, or both — then explains the causes specific to a city water supply, and says plainly where the fix is a plumbing part or a call to your utility rather than a filter.
Pick the symptom you have
Why does my tap water smell like rotten eggs?
- Hot tap only:
- Your water heater, not your water
- Cold tap only:
- Hydrogen sulfide arriving through the cold line
- Both:
- Something upstream of the water heater — or the drain
Why is my tap water cloudy or milky?
- Hot tap only:
- Dissolved air coming out of solution
- Cold tap only:
- Aerated water, or fine suspended sediment
- Both:
- A change on the supply side
Why is my tap water brown?
- Hot tap only:
- Sediment inside the water heater
- Cold tap only:
- Iron and manganese resuspended in the pipes
- Both:
- A supply-side event
Why is my tap water yellow?
- Hot tap only:
- The water heater is shedding
- Cold tap only:
- Metals or natural color arriving with the water
- Both:
- A change on the utility's side
Why does my tap water taste metallic?
- Hot tap only:
- The tank and the hot-side pipework
- Cold tap only:
- Water that has been standing in your own plumbing
- Both:
- Something upstream of your plumbing
Why does my tap water smell like chlorine?
- Hot tap only:
- Heat drives the smell out of the water
- Cold tap only:
- Fresh, recently disinfected water
- Both:
- A change in how the system is disinfected
Need whole-house or professional water treatment?
For the problems a pitcher or under-sink filter cannot fix — scale, rust and black staining, sulfur smell, well contamination, or test results you cannot explain. Tell us what is happening and we will connect you with a local water-treatment professional.
These pages are written for homes on a city water supply. If you are on a private well, the causes and the fixes are different. Diagnose private-well water by symptom.
If you have been told to boil your tap water, that is a different situation from the symptoms above. What a boil water advisory means and what to do.
By TapWaterData Team
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