What causes water to taste or smell weird?
Occasionally, you might notice your water has an abnormal taste or odor. This is not uncommon, and there could be any of several reasons - some regional - causing the unusual taste or odor.

The Washington State Department of Health offers this advice: 

If a taste or odor occurs at every water faucet on the property, the cause is probably the main water supply. If it occurs only in certain faucets, the problem is the fixtures or pipes supplying those specific faucets. If the problem goes away after running the water for a few minutes, the problem is somewhere in your household plumbing system. The best way to reduce taste and odor caused by your plumbing is to run the faucet for several minutes, put some water in a container, and then store it in the refrigerator. You may also consider installing a certified water filter.

What are likely causes for common taste and odor issues?

Taste and odor in the distribution system

Taste or Odor Description	Most Likely Causes	Most Common Corrective Actions
Chlorinous/ Swimming Pool/Oxidant/Ozonous	High chlorine or disinfectant residual	New main with high chlorine may need flushing
Earthy/Musty Fishy/Grassy/Hay/Straw/Woody/Fragrant/ Vegetable/Fruity/Flowery	Algae in reservoir or storage tank	Cover reservoir, clean storage tank
Cat Urine/Kerosene (distribution system problem but controlled at the treatment plant)	Change to chlorine dioxide, release of chlorine dioxide at faucet and reaction with volatiles for new carpet or home remodeling	Advise about disinfectant change (chlorine dioxide issue)
Chemical/Hydrocarbon, Petroleum	New lining on pipes or tanks, lubricants, gasoline	Gently flush new linings, cure new coatings, use approved lubricants, check for gasoline source, cross-connection
Sweet, Chemical	MTBE, antifreeze, or other substance contamination	Eliminate contamination source, cross-connection
Marshy/Swampy/Septic/Sulfurous	Biological growth in reservoir or storage tank Low-oxygen condition Control algae, clean tank	Correct low-oxygen condition, oxidize, improve tank or reservoir water use and turnover
Chemical/Solvent/Plastic	New plastic pipes, permeation of plastic service line by contaminated soil	Flush new pipes, remove contaminant from soil, replace pipe with copper
Wet Paper/Paint-like	Pipe joint lubricant	Flush, change lubricant
Shoe polish/Solvent	Coal tar pipe lining	Flush until lining is cured

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Information in table above is from AWWA’s Water Quality Investigator’s Field Guide)

Taste and odor in private plumbing systems

Taste or Odor Description	Most Likely Causes	Most Common Corrective Actions
Astringent/Pungent/Chalky/Cooling/ Metallic, Metallic Mouthfeel	Corrosion of copper or galvanized piping Metals, iron, copper, etc.	Customer may be adding chemicals for home treatment, improper electrical grounding, corrosion; carbon dioxide backflow from tank may cause metals increase
Chemical/Hydrocarbon	New plumbing, lubricants, gasoline, cross-connection	Gently flush new linings, cure new coatings, use approved lubricants, check for gasoline source, check for cross-connection
Sour/Acidic	Low temperature in hot-water tank or other problem, home treatment device	Adjust hot water temperature, flush tank, check home treatment device
Marshy/Swampy/Septic/Sulfurous	Low-oxygen condition, home treatment device, stagnant plumbing, water heater	Correct low-oxygen condition, oxidize Check home treatment device, flush water heater, flush plumbing
Salty	Malfunctioning water softener	Maintain home water softener; private reverse osmosis system may malfunction
Chemical/Solvent/Plastic	New plastic pipes	Flush new pipes
Cat Urine/Kerosene	Chlorine dioxide used, release of chlorine dioxide at faucet and reaction with volatiles for new carpet or home remodeling	Chlorine dioxide issue, may consider using another disinfectant

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Information in table above is from AWWA’s Water Quality Investigator’s Field Guide)