Why Does My Water Bottle Smell?

Plastic or metal, attempting to drink water from a smelling water bottle is always unpleasant. It is enough to ruin a perfectly cooked meal and discourage you from hydrating on a stressful day.

Why Does My Water Bottle Smell

Your initial reaction may be to question the contents of the bottle, but there are several reasons your bottle may be emanating a foul smell.

This article would discuss all the possible causes of a foul-smelling bottle. You can also expect to find a detailed explanation of the different smells and their origin.

Reasons Why Water Bottles May Smell Bad

There are two leading reasons for a water bottle to smell, and they are:

  • Bottle Hygiene
  • Water Quality

Bottle Hygiene

Good hygiene is critical when using reusable water bottles. This is because water is an excellent substrate for bacteria and mold. Without proper hygiene and regular cleansing of the bottle, microorganisms will grow and corrupt the taste and smell of water in the bottle.

Smell due to bacterial growth can occur in both metal and plastic reusable water bottles. This is because the bottle receives bacteria from different surfaces, and the most common source is the indigenous bacteria present in your mouth.

When you drink water directly from the bottle and the rim regularly comes in contact with your mouth, there would be bacterial transfer from the mouth to the rim.

With time the microorganisms begin to accumulate and grow around the rim. Bacteria are microscopic, so you may not be able to see them, but an unpleasant smell around the rim of your water bottle is a sufficient indication of bacterial growth.

You can correct the unpleasant rim smell of a water bottle by filling it with white vinegar and leaving it to soak overnight. Microorganisms cannot survive in the harsh acidic condition of the vinegar and would perish. In the morning, you can wash away the smell of vinegar with soap and water. The bottle should smell clean and fresh after rinsing.

On rare occasions that the entire bottle smells, it means bacteria from the rim have settled at the bottom of the bottle. Therefore, you will need to perform a thorough cleaning of the bottle.

Add one teaspoon of bleach and one teaspoon of baking soda to your bottle and fill with water. Shake vigorously and leave to soak overnight. In the morning, scrub the insides, cap, and rim of the bottle with a brush, then rinse with warm water. Your bottle should have a fresh smell once done.

Water Quality

Sometimes the bad smell of your water bottle may not come from the bottle itself but the water contained in it. You can determine this by observing the smell of your bottle without the water and the smell of your bottle with the water.

Regular water shouldn’t have a smell, but if it does, there is either a problem with the water’s source or its composition.

Contrary to popular belief, most of the available potable water isn’t 100% pure. In fact, it not advisable to drink 100% ultrapure water. Instead, it should contain elements and compounds that provide benefits to the body. These elements are usually odorless, and if present in the correct quantity, do not affect water’s smell.

However, if a foreign object or an unusual element/metal is introduced to water, it becomes an impurity that can produce an unpleasant odor. Here are examples of common foreign components in water and the different types of smell they produce:

1. Chlorine (Water Bottle Smells Like Bleach):

Chlorine is a popular disinfectant used for killing bacteria, viruses, and other microorganisms present in water. Its compounds are obtained from seawater, but since chlorine is not a natural drinking water component, it is regarded as foreign – a beneficial foreign additive.

Chlorination is done by adding a specific amount of chlorine to the water. The quantity of chlorine added to water determines its effectiveness, and it is recommended that 4g of chlorine is enough to sterilize 1000 liters of water. At that concentration, the water adopts a slight taste and smell of chlorine, but it should be minimal.

Reasons Why Water Bottle Smells

Suppose your water bottle has an overpowering smell of chlorine. It could mean that your water provider added more chlorine than necessary.

This should be communicated to them so they can make the right changes. Until it is corrected, adding the water to your bottle would make it smell of chlorine.

2. Sulfur (Water Bottle Smells Like Rotten Egg):

This smell is particularly common to water sourced from the ground. Sulfate compounds and sulfate-reducing bacteria are naturally present in groundwater, and smelling them in your drinking water signifies a high level of pollution. If the water was adequately purified, the bacteria and compound should have been filtered out.

In the scenario that the water was purified correctly, and your water still has a rotten egg/sulfur smell, it signifies the presence of sulfate-reducing bacteria in your plumbing.

The bacteria dwell in oxygen-deficient environments and produce hydrogen sulfide gas during metabolism. Hydrogen sulfide gas has a rotten egg smell that would corrupt the scent of water in any pipe or bottle. Figure out the source of the smell and avoid bottling such water.

3. Foreign Metals (Water Bottle Smells Like Metal):

Some elements such as sodium, iron, and magnesium are part of the chemical components of drinking water. They exist in small quantities and do not make water smell bad.

However, if your water contains high lead levels, mercury, arsenic, and copper, it will develop a metallic taste and smell. Manganese and zinc can also produce a metallic smell.

Alternatively, the pipes employed for your plumbing could be responsible for the bad metallic smell of your water. Your pipe may react with the components of your drinking water and produce chemicals that would contaminate the water and create a bad smell.

4. Waste (Water Bottle Smells Like Sewage Or Fish Tank):

When water is exposed to decayed organic matter or algae, it adopts a highly unpleasant smell. Algae is a popular term that refers to a group of photosynthetic bacteria that grow on water.

Algae produce blooms (called algal blooms) that linger in the smell of water even after treatment. Algal blooms have a light earthy, mildew smell. However, if your water bottle has an overwhelming fish tank smell, your drinking water may be contaminated with algae.

This could be from their growth in your water system or sink. The possibility of this happening is low, but if it does happen, it may lead to skin irritation, diarrhea, vomiting, fever, and many other gastroenteritis symptoms.

Generally, if your water bottle starts to taste or smell like waste disposal, you should stop drinking water from it. First, figure out the source of the problem, correct it, then resume drinking.


When a water bottle smells, it discourages people from drinking from it. Avoid this by washing the bottle after every use and performing a cleanse for it periodically.

Also, transfer good quality water into the bottle, and avoid leaving your bottle in messy areas.