There’s nothing more off-putting than turning on your faucet and catching an unpleasant whiff from your water supply. Smelly water certainly won’t encourage you to stay hydrated.
If you’re wondering why your cold or hot water smells, and most importantly, how to fix it, you’ve come to the right place. We’ll be sharing all the most common causes of smelly water, and how to get rid of the smell once and for all, in this guide.
📖 TL; DR
Smelly water is typically caused by hydrogen sulfide, disinfection chemicals, organic matter, bacteria, and heavy metals. You can fix smelly water by installing a water treatment system or cleaning your pipes or drains.
Table of Contents
👃 Why Is My Tap Water Smelly?
You can find the most common drinking water odors and their causes below.
A sewage odor in your drinking water could be caused by bacteria buildup in your water heater or stagnant water in your heater. If you’ve been away from home for several weeks, or you shut off your heater to save energy, bacteria growth is especially likely.
Some people confuse the rotten egg smell of hydrogen sulfide with the smell of sewage. So, if you think your water smells like sewage, it could also be contaminated by hydrogen sulfide.
On a serious note, a sewage odor could be caused by sewage itself – especially if you own a private well located next to an overflowing or improperly located septic system.
Alternatively, the sewage odor might be caused not by your water itself, but by the bacteria and organic matter in your kitchen sink drain. This odor often becomes more obvious when water runs into the drain, making you assume that the smell is coming from your water.
A chlorine odor, or a swimming pool smell, is – no surprises here – caused by chlorine. Most public drinking water supplies are disinfected with chlorine or chloramine. These chemicals keep our water safe from microbiological contamination, but many people find the smell of chlorine unpleasant.
If the chlorine odor disappears after running your water for a while, it might be that you’re smelling the chlorine buildup in your pipes when you immediately switch on your faucet.
A musty or earthy water smell is a sign of algal or bacterial growth in your pipes. Typically, this algae or bacteria doesn’t pose a health threat, but it can still be unpleasant to smell in your water.
Rotten Egg Odor
If your water smells like rotten eggs, it’s likely contaminated by sulfur. The sulfur smell is one of the most unpleasant water smells, and typically indicates the presence of hydrogen sulfide or sulfur bacteria.
These contaminants are usually found in well water sources, depending on the natural groundwater chemistry.
A metallic taste and smell in your water is probably caused by corroding zinc, copper, iron, or manganese in old water supply lines.
Trace amounts of these metals generally aren’t harmful, but most people don’t enjoy a metallic taste in their water. Your water is more likely to smell like metal if it has a low pH.
The two most common causes of a fish-like smell in your water are chloramine, used to disinfect municipal water supplies, and organic matter, such as decaying plants and leaves.
Chloramine is the most likely culprit of fishy city water, while organic matter is the likely cause of fishy well water.
Fuel-like odors in your water are (thankfully) the least likely odors you’re likely to come across. A leaking fuel tank or an underground fuel storage tank located too near your well are two possible causes of a fuel-like odor in your well or plumbing system.
🚱 How to Find Out the Cause of Smelly Tap Water
The best way to find out the cause of your smelly water supply is to test a water sample from your faucet.
You can use our guide to narrow down your testing to one or several contaminants, based on how your water smells. Or, if the smell is unusual and you can’t detect it, buy a test kit that detects all the most common contaminants in your water supply (either city or well water).
We recommend Tap Score’s testing kits to anyone looking for a comprehensive analysis of their water’s odor-causing contaminants. Tap Score’s laboratory tests give a detailed report of your water’s impurities and parameters, including how their quantities compare to national regulations and how to remove them from your water.
⚗️ Is Smelly Tap Water Safe to Drink?
Whether or not smelly tap water is safe to drink depends on what is causing your tap water to smell, and how much of that contaminant is present.
For instance, if your tap water smells like rotten eggs, it probably contains hydrogen sulfide gas, which is safe to drink in small-to-moderate quantities – but has side effects if consumed in excess.
On the other hand, if your tap water smells like sewage, you might have bacteria growing in your plumbing system or hot water tank. In this case, your water could be dangerous to drink, and could make you sick.
The only way to know whether your smelly water is safe to drink is to test your water, then compare the test results to the EPA’s Maximum Contaminant Levels.
🧪 How to Fix Smelly Tap Water
To fix smelly tap water, try one or several of these methods, depending on the odor and the contaminants detected.
Locate the Source of the Smell
Before you start looking at solutions for smelly drinking water, narrow down the cause of the smell by determining where the smell is coming from:
- If the smell is coming from all faucets, and the odor doesn’t go away after running your faucets for a few minutes, your odor source is either your plumbing system or your water itself.
- If the smell is coming from all faucets, and the odor goes away after running your faucets for a few minutes, the odor source is likely your plumbing system.
- If the smell is coming from all hot faucets, the odor source is likely the magnesium rod in your hot water heater.
- If the smell is only coming from certain faucets, and the odor goes away after running your faucets for a few minutes, the odor source is likely somewhere in the pipes or fixtures that supply these specific faucets.
Run Your Faucets
There are several reasons why stagnant water in your plumbing system can start to smell. Chlorine reacting with the organic materials in your water pipes, metal leaching in stagnant water, and contamination from your water heater may all give your water an unpleasant smell.
Running your faucets for a couple of minutes will get water flowing through your pipes and bring a new, fresh supply of water into your home, eliminating bad odors.
Clean Your Water Heater
Bacteria growing in your heater will give your hot water an unpleasant, sewage-like smell. To remedy this issue, hire a plumber to inspect and service your heater. If your heater contains a magnesium rod, your plumber will probably suggest replacing it with a rod that won’t smell, such as an aluminum or zinc rod.
Clean Your Well Storage Tank
If you have a private well and your water has a musty or earthy odor, periodically cleaning and maintaining your well storage or pressure tank may solve the issue. If well tanks aren’t cleaned regularly, they may harbor bacteria, fungi, or algae, which give water an unpleasant smell.
Clean Your Drains
You may think your water smells bad, but it might be your drains that are to blame. Use a commercial drain cleaner or a mixture of baking soda and white vinegar to flush the drains in your kitchen and bathroom sinks. This should remove a buildup of old food, hair, and organic matter from the plugs and pipes, eliminating the unpleasant whiff. If you have an overflow in the sink, common in bathrooms, be sure to pour the solution there as well.
Shock-Chlorinate Your Water
Sometimes, bacteria in water can produce an unpleasant smell, especially if it’s combined with iron. Shock-chlorinating your water is the best defense against bacteria contamination.
👉 Follow the instructions in our guide to disinfect your well water supply with chlorine.
Contact your Water Supply Authority
If you get your water from a city supplier and you’ve noticed a sudden change in the smell, taste, or quality of your water, contact your water supply authority to discuss these changes and ask for an updated Water Quality Consumer Confidence Report.
Install a Water Treatment System
Most odor-causing contaminants can’t be removed at the source, but that’s okay – you can still remove them in your home. There are several types of water treatment systems that are ideal for treating a smelly, contaminated water supply:
- Activated carbon filter cartridges, found in gravity filters, whole home filters, and under sink filters, can tackle the chlorine smell and taste in municipal drinking water. See our top picks of the best water filters in 2023 right here.
- Iron filters, like air injection and chemical injection/oxidation filters, can tackle a metallic smell caused by iron and manganese, and will also prevent orange staining. Check out the best systems here.
- Chlorination systems, to remove sulfur bacteria and other smelly microorganisms, followed by an activated carbon filtration system to eliminate the chlorine smell
- Reverse osmosis systems, which remove virtually every single contaminant that could contribute to poor water smells in your water supply, including chlorine, pesticides, iron, and sulfur (these systems need pre-treatment if treating well water). See the top RO systems in this round up.
Contact your County Health Department
If your water has a gasoline or fuel-like odor, get in touch with your county health department immediately. Stop drinking your water while the issue is investigated.
🧠 How To Fix Smelly Tap Water: FAQs
What does it mean when your tap water smells bad?
Smelly tap water could mean a number of things, depending on what smell you can detect. If only your hot water smells, you may have an issue with bacterial growth in your heater or a smelly magnesium heating rod. If your hot and cold water smells like rotten eggs, your water supply may contain hydrogen sulfide gas. A sewage smell in your hot and cold water could be caused by bacteria, hydrogen sulfide, or a buildup of organic matter in your kitchen sink drain.
Why does my water stink when I turn on the faucet?
Your water may stink when you turn on the faucet due to a buildup of bacteria, chlorine, or organic matter in your water supply line, or heavy metal leaching from your pipes into your stagnant water. Any of these options are likely if the bad smell goes away when you’ve ran your faucets for several minutes.
How do you get rid of rotten egg smell in water?
An effective way to get rid of a rotten egg smell in your drinking water is to use an air injection/oxidation water filtration system to treat your entire water system. AIO systems can remove between 3 and 7 PPM of hydrogen sulfide – more than what you’d expect to find in your water supply.
Is it OK to drink water that smells bad?
It’s sometimes okay to drink water that smells bad – but this entirely depends on what your water smells like, and where it’s come from. If your water smells like sewage, or has a musty or fishy odor, you shouldn’t drink it until you’ve tested it to find out what it contains. If your city water has a faint swimming pool smell, or if the smell clears after running your water for several minutes, it’s fine to drink.
Why does my faucet water smell like sewage?
A sewage-like odor generally comes from bacteria growing in your water heater, bacteria growing in your drain, or hydrogen sulfide in your source water. If you notice a new, obvious sewage smell in your water supply, stop drinking it and conduct a bacteria test as soon as possible.