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It's hard to get trustworthy advice when it comes to your drinking water, so we made Tips for Taps to help answer your questions.
Order a Tap Score Water Test and receive personalized support from professional engineers and scientists by phone, email and chat.

Stinky Water: Your Odor Guide

Whether it stinks like rotten eggs or bleach, smelly water might have you worried.

The exact cause of water odors can be challenging to determine. Therefore, we have created a handy guide to help you identify and treat common causes of household water smells, as well as what to do about it.

How to locate the source of smelly water:

The first step to solving a smelly water problem is determining where the smell is coming from. Here’s a chart that can help you locate potential sources:

Water Odor Chart

Common Water Odors and Ways to Fix Them:

Water Smells like Bleach, Chlorine, or Medicine

Chlorine is used by most public water suppliers to prevent bacterial growth. When added to a well (via shock chlorination) or plumbing system, chlorine produces a strong bleach odor.

The best way to eliminate the chlorine smell is turn on your faucets (preferably outdoors) and let the water run until the smell is gone. In some cases, chlorine interacts with organic materials that have accumulated in your plumbing system, which increase the musty-bleach smell.

Volatile Compounds Water TestConcerned about the effects of chlorine? Learn more here and take a look at our test specifically targeting chlorine disinfection byproducts. If your water comes from a public water supply, you should contact your water supply authority.

If you get your water from a well and are smelling a chlorine or bleach odor, you may need to have your water system flushed.

Water Smells like Rotten Eggs

Generally, a sewage-like or rotten egg odor in your tap water results when sulfur-reducing bacteria grow in your drain, water heater, or well. These bacteria, which use sulfur as an energy source, chemically change natural sulfates in water into hydrogen sulfide-which emits a distinct rotten egg odor.

Hydrogen Sulfide bacteria water testIf your water smells like rotten eggs, we can help! We have a specifically targeted, at home, self-testing kit for hydrogen sulfide bacteria

Bacterial growth in the drain:

This is the most common cause for these types of odors. When organic matter (hair, soap, food waste etc.) accumulate in the drain, bacteria can thrive and produce gas that smells like rotten eggs.

How to address and remove bacteria in the drain:

  1. Making sure bacteria growth in the drain is the issue:
    Both the cold and hot water smell (at a single tap), and that the smell is not coming out of all faucets. Then, fill a glass with water from the faucet that does smell and step away from the sink so you can't smell any residual odor from the tap. Swirl water inside the glass a few times. Wait 30 seconds–and if the glass no longer smells, then this test suggests you likely have bacteria in the drain causing the smell.

  2. If the water in the glass does not have an odor, the best plan of action is to disinfect and flush the drain.


Bacterial growth in your water heater:

When hot water goes unused, bacteria in your water heater can produce a rotten egg or sewage-like smell. This occurs if your water heater is turned off for a significant amount of time or if the thermostat on the heater is set too low. These bacteria are generally not a health threat.

How to address and remove bacteria in your water heater:

Making sure bacteria growth in the water heater is the issue:

  1. Your hot water smells, but your cold water does not.This generally means that the smell originates from the magnesium heating rod in your hot water tank.
  2. If only your hot water smells...Call a plumber to replace your magnesium heating rod with an alternative, like an aluminum rod.


Bacterial growth at the water source:

If none of the above steps lead to an answer, the odor may be from your water source itself. If this is the case, do not use or drink the water until you test your water–as it may contain harmful bacteria.

Microbiology Water TestIf this is the case, take a look at the Tap Score Total Microbiology Screen Water Test. This all-inclusive pathogen and microbiological screening provides identification and enumeration of thousands of species of bacteria, protozoa, algae and more in tap water, well water, and other surface water.

Recommendation if your source is a private well:

  1. Treating your well with shock chlorination (take a look at this step-by-step guide to disinfecting your well) because the natural chemistry of your groundwater may be supporting bacterial growth.
  2. Contacting your local health department in case a defective or improperly located septic system is located near your property.

    Recommendation if your source is a public utility:

    1. Contacting your water supply authority or county health department.
    2. Try to identify if your water source has been switched or if algal blooms have affected your water system’s water supply.


      Water Smells Musty, Moldy, Earthy, Grassy or Fishy

      When your water smells this way it is very likely that bacteria is present. Reasons your water may smell moldy include:

      Decaying matter in your drain:

      This is the most common cause for moldy smelling water. The best way to combat decaying matter in your drain is to disinfect, clean, and flush your drain.

       Private well? Well water pollution from surface drainage: Moldy water can be attributed to certain types of algae, fungi, or bacteria growing in your water supply–particularly during warm weather. We recommend treating your well with shock chlorination. If the problem persists, you may want to install an activated carbon filter or an automatic chlorinator (followed by an activated carbon filter).

       Public water? Insufficient chlorine: If you are on a public water supply, certain types of bacteria may grow in your supply line if an insufficient amount of chlorine is added. If you suspect this is the case, contact your water supply authority.

      How do you know how much chlorine in your water? Testing directly at the tap is the most accurate way. While we usually suggest testing your water a certified laboratory, chlorine is best tested at some due to its volatile nature. Take a look at our DIY chlorine test strips–they are included in every Tap Score City Water Testing package. They are also available as an add-on for any test here.

      Water Smells like Gasoline or Petroleum

      These odors are rare, but could be very serious. If you are on a public water supply, contact both your water supplier and county health department immediately. Fuel-like odors may be due to:

      1. A leaking underground fuel storage tank near your well
      2. Contamination due to discharge from factories landfills
      3. Runoff from agriculture leaching into your water supply

      If any of these are the case, stop drinking the water, as it may have adverse health effects, including:

      • Anemia
      • Increased risk of cancer
      • Liver and kidney problems

      Do you need help with smelly water?

      Drinking water odors may come from a variety of reasons–some harmless, while others are potentially serious. If you aren’t sure the cause of stinky water or not sure how to treat it–send us a message at

      Talk to an expert

      It's hard to get trustworthy advice when it comes to your drinking water, so we made Tips for Taps to help answer your questions. Order a Tap Score Water Test and receive personalized support from professional engineers and scientists by phone, email and chat.


      May 14, 2020 • Posted by Jennifer kozlowski

      Our power went out leaving us to have to flush well to restart when filling we accidently poured a water jug in that had some gasoline in it. Now we can not get the smell to go away from our water faucets while running water.
      We can only get it to go temporarily and it comes back.

      May 14, 2020 • Posted by Lori Gutierrez

      My water doesn’t smell like rotten eggs or chlorine but it does have a string strange odor I cannot predict…i had my water tested .it came back fine but it smells still? What should I do?

      May 14, 2020 • Posted by Shirley Fountain

      My water has a bad smell and it’s making me sick to smell it, smell like it got fuel smell and something dead, please help me!

      Jan 13, 2020 • Posted by Neva

      I live in a back woods country town Mountain Home, Arkansas (Baxter County). Our water department smells of gas or propane. There’s alot of complaints about it and nothing is done about it. They say it’s allowed to smell like gas, propane. Kids and alot of poor people bath, and use this water to eat and drink from. This town is going down hill in a fast roller coaster ride with no brakes.

      Jan 13, 2020 • Posted by Linda Roberts

      My water has a weird smell to it, mainly coming from the kitchen and dishwasher. Cannot eat off of plates because the smell seems like its bedded in after being washed in the dishwasher. The kitchen faucet has the smell, gets on your hands if you wash them in the kitchen. Do I need to get the water tested?

      Jan 13, 2020 • Posted by J

      Water source from all faucets including washer have a musty, mildew smell when showering or not in use? I’m on septic. Have a 5 year old water heater that have started to leak ? What is going on? Please help Thank you

      Dec 07, 2019 • Posted by Les peterson

      We have city water, our bathroom faucet water smells like sewer for about a min or so and then is good. How can we fix it?

      Apr 28, 2019 • Posted by Julio (Tap Score Team)

      If the rotten egg smell is limited to your bathroom, it sounds like it could likely be a bacterial issue. We recommend performing a basic Essential test along with a sulfur bacteria self-test (added on to the essential test).

      Apr 28, 2019 • Posted by Rose Daye

      The development where I live the bathroom water smells like rotten eggs. I feel that when i shower that i stink like that. The smell is only n my bathroom.
      What should i do, and who do I contact concerning this matter.

      Nov 16, 2018 • Posted by Richard C. Beck

      City tap-water’s chlorine odor can be modified by pouring the tap-water into a very clean gallon jug and let it sit at least overnight. Then NO chlorine odor or taste as the chlorine gas degassifies from the jug without having a lid. Do not fill water into the water jug and up to the very top of the jug. 7/8 gallon of tap water, yes. That jug’s filling will have a stored tap-water’s surface area for degasifying, Yes!

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