For instance, petroleum or gasoline smell or taste in water is rare and could mean that your water supply may be contaminated by an underground pipe that’s leaking with byproducts of gasoline or other fuel products. Now this definitely poses a health risk. Stop drinking the water and contact your local health agency and local water supplier immediately.
Metallic taste in water like iron or copper could come from traces of metals from which your pipes are made; and consuming too much copper through your water over time could cause headaches, nausea, and diarrhea. Get a sample of your water analyzed by a certified lab to determine the concentration levels.
Tap water that smells or tastes like rotten eggs or sulfur most likely contains hydrogen sulfide; a chemical that is released when a certain kind of bacteria is present in the water system. Water heaters contain an element that protect them from corrosion, which breaks down over time especially when your water heater is not used for a long period of time causing bacteria to thrive. When this happens, a chemical called hydrogen sulfide is released and gives off a nasty rotten egg smell.
Not all unpleasant smell and taste in water come from chemical sources. Some nasty smell and taste may come from bacteria from your water source. Nearby livestock, fish pens, or sewage treatment plants may cause your water to smell like moldy earth, sludge, or smell fishy.
Tap water contaminated with organic matter is usually harmless. Water that has a salty taste is not usually a cause for concern. A salty taste in your water may simply indicate naturally high levels of sodium, magnesium, or potassium in the water in your area especially if you live near the seaside.