It is important to determine if the odor exists in the public water supply, premise plumbing, environment (potential drain odor).

  • Odors that are consistently noticed at every faucet including the front hose bib are typically  caused by the water supply
  • Odor noticed in only one or several, but not all, of the faucets is internal to your house
  • Odor that goes away after running the water for several minutes is also internal to your house
  • Odor that goes away after you step away from the sink is often coming from the drain

If your plumbing is the source of the odor, you can try to flush the plumbing system or you can consult a licensed plumber. Contact CCWD at (925) 688-8156 if you suspect the water supply.

Test for Odors

When you detect an odor in your tap water, we recommend that you perform what we call a glass test at the faucet.

  • Get a clean glass
  • Run the cold water tap for 2 minutes
  • Fill and rinse twice with cold tap water
  • Fill the glass and turn off the faucet or hose bib
  • Step away from the sink. This eliminates the possibility of mistaking odors from your drain for odors in your water
  • Smell the water in the glass and characterize the odor, if any

Chlorinous, Bleachy, Chemical or Medicinal  Taste/Odor
There are two common causes for a chlorinous, bleachy, chemical, or medicinal taste or odor in the water.

  • Addition of chloramine (total chlorine) that we use to disinfect the water to ensure that it is safe to drink
  • Interaction of chloramine with a build-up of organic material in your plumbing

If the problem is the water supply, it will occur at every faucet and will not go away after a few minutes of running the water. An easy way to get rid of the chlorine taste and smell is to let water sit in a glass for a few minutes. Then, put the water in a covered container and chill it in the refrigerator. Cold water tastes and smells better than water at room temperature.

Although the total chlorine level is a fraction of what is found in pools and spas, you may occasionally detect the smell of chlorine in your water. This odor may be particularly strong in the shower since chlorine is released to the air more rapidly when mixed with hot water.

Foul, Sulfurous, Rotten Egg, and Sewage Odor 

  • Cold Water:If the odor is not evident in the glass, but is noticeable when the cold water is running and you are standing at the sink, then the odor is most likely coming from the drain. To disinfect your drain: 
    1. Run cold water for 15 seconds then turn if off.
    2. Pour one to two cups of liquid laundry bleach down the drain(s) that smell. Pour the bleach slowly around the edges of the drain so that it runs down the sides. Be careful when you handle the bleach because it can irritate skin and damage clothing.
    3. If the smell is coming from a sink with a garbage disposal, turn the disposal on while the bleach is poured. This will spread the bleach around.
    4. Let the bleach sit in the drain for about 10 minutes ─ no longer.
    5. After 10 minutes, run the hot water for a few minutes to flush the bleach. Run water down the garbage disposal drain for the same amount of time.
    6. Repeat these steps if again if necessary.
  • Hot Water:If you find these odors in your hot water, there are two probable causes:
    • Bacteria may be residing in the water heater. Disinfecting the water heater may eliminate this odor.
    • The water heater anode may need to be replaced. If experienced, inspect the anode yourself; otherwise, call a plumber.
Back to Troubleshoot Water at Your Tap

Show All Answers

1. Taste
2. Odor
3. Earthy, Musty, Moldy, Grassy Odor
4. Gasoline, Turpentine, or Organic Solvent Odor