Why does my water smell or taste fishy?
A fishy smell usually comes from natural organic matter from a lake or reservoir source, sometimes reacting with chloramine — and occasionally from metals like barium or cadmium.
The likely causes
Decaying vegetation from a surface-water source can react with the chloramine disinfectant to produce a fishy odor.
Seasonal algae in the source water can give a fishy or swampy smell — usually harmless but unpleasant.
Less common: these metals can occur naturally in groundwater and carry a faint fishy taste. Both have health limits.
Is it dangerous?
Most fishy odors are aesthetic and tied to the natural source water. It becomes a health question only if metals like barium or cadmium are involved, which a test would show.
How to tell what it is
A fishy smell that tracks the seasons points to organic/algae sources. A lab test rules in or out barium and cadmium if you want certainty.
The fix
Activated-carbon filtration handles the organic-matter odors; reverse osmosis additionally removes barium and cadmium if a test shows them.
Also searched: water smells like fish · water tastes fishy · water smells like a lake