Chlorine Odor in Pools: What It Means and How to Fix It

Almost everyone enjoys spending a hot summer’s day in or around a pool. The splashing, diving, laughing, and of course, that “pool smell.” Many say they can smell if too much chlorine is in the water. But how true is this when a pool smells like chlorine?

If a pool smells like chlorine, it is a clear sign that there is too little chlorine in the water. The “pool smell” comes from chloramine, which results from chlorine reacting to body sweat, urine, and cosmetics. These chloramines can cause skin and eye irritation, swimmers ear, and diarrhea.

Read on to discover what causes this chlorine smell, how to prevent it, and how chlorine disinfects the pool water.

What Causes The Chlorine Smell Around A Pool?

The familiar “pool smell” that many associates with too much chlorine in the water is not actually from too much, but rather too little chlorine. The “pool smell” comes from chloramines, a chemical compound that can form in pool water.

Chloramine forms when chlorine comes into contact with high enough doses of cosmetics, perspiration (sweat), tanning lotions or oils, and urine. Chlorine is added to water to disinfect and destroy germs, but if there are high levels of these unwanted additions, the chlorine breaks down into chloramines. These chloramines are what give off the chlorine or “pool smell” odor.

How Does Chlorine Disinfect Pool Water?

Adding chlorine to pool water releases two active bacteria-killing chemicals, hypochlorous acid, and hypochlorite ion. When these two chemicals combine, they are known as “free Available Chlorine” (FAC). The FAC is what actively sanitizes the pool water; thus, it is essential to maintain proper FAC levels.

When there are too many contaminants in the water, the FAC is unable to cope. This is due to the FAC levels being too low to be effective in killing all the bacteria. Hypochlorous acid combines with the ammonia from urine and sweat, forming chloramines, also known as Combined Available Chlorine (CAC).

Chloramines are not great at disinfecting pool water. This is noticeable in the form of skin (red skin) and eye (red-eye) irritations, along with a strong “pool smell.” If a swimmer is overexposed to high levels of chloramines, it could lead to respiratory problems such as asthma. So it is vital to maintain the proper levels of chlorine in pool water to prevent health problems.

How To Prevent Chloramines In Pool Water?

It is important to prevent chloramines from forming in the pool water as they can have adverse health effects and a chlorine smell. The swimming Pool and Hot Tub Alliance recommends the following levels of chlorine.

FAC concentrations in pool water should remain between 1.0 – 4.0 parts per million for chlorine to work effectively (FAC should never fall below 1 part per million). CAC levels should be less than 0.2 parts per million. The following will assist in ridding the water of chloramines.

Shock The Pool Water Regularly

Shocking the pool water weekly is recommended to remove contaminants and ammonia. This will increase the FAC levels, thus reducing the level of CAC in the water and leaving the water odor free and sanitized.

Switch To A Non-Chlorine Shock

There are many shock treatment options on the market, some being chlorine-free. This may be preferred by many who may be sensitive to chlorine. Changing from chlorine to a non-chlorine-based shock treatment may better suit your needs and solve the “pool smell” odor.

Use A Pool Water Sanitizer

Another method to enhance pool water quality is to use a water sanitizer. AOP (advanced oxidation process), UV, or ozone are great alternatives to sanitizing pool water. These methods will reduce the amount of chlorine in the pool water and kill bacteria. This may be a slightly more expensive way to sanitize pool water, but it is highly effective, just like chlorine.

Test The Pool Water Regularly

Testing the pool water regularly will prevent chloramines from reaching high levels. This will give you the upper hand and prevent the dreaded “pool smell,” and keep the water crystal clear.

Shower Before Swimming

Having a shower before diving into your pool will assist in washing all the oils, sweat, and dead skin from swimmers before entering the water. This is not always followed, so still do regular water testing to be on the safe side.

How To Control If There Is Too Much Chlorine In The Water

Not only can insufficient free available chlorine (FAC) levels in pool water be a problem, but excessively high level of chlorine can be dangerous as well. High chlorine levels may cause eye and skin irritation and trigger asthma. Some people may think they can detect high chlorine levels through smell or sensation, but the best way to accurately determine chlorine levels is to test the water.

The most straightforward test is a chlorine test strip. These are very accurate and give a result in seconds. Follow the steps below on how to use a chlorine test strip.

  • Remove the pool cover and allow the pool to get some sunlight
  • Wash your hands with soap to remove any contaminants
  • Remove a test strip from the container
  • Hold the test strip in your fingers and dip your hand into the water up to your elbow. This is the best depth for the chlorine test
  • Keep the test strip under the water for 10 to 20 seconds
  • Remove the strip from the water and place it down horizontally out of direct sunlight
  • Equate the color of the test strip to the indicator on the container
  • The color chart will indicate whether chlorine levels are high, low, or in range.

If the chlorine levels are slightly higher than recommended, let the sunlight do the work for you. Sunlight or UV light can remove up to 90% of the chlorine from water. An uncovered pool can lose more than 50% of its chlorine in 2 hours on a hot summer day.

This is why it is vital to test the pool water regularly. Regular testing will ensure optimal chlorine levels are maintained for a crystal clear pool all year round.


If your pool smells like chlorine, there may not be enough bacteria fighting chlorine in the water. Chlorine reacts with ammonia found in cosmetics, oils, sweat, and urine to create chloramines. These chloramines are what create the “pool smell” and are a sign that there is not enough chlorine in the pool water. A clean and sanitized swimming pool should not have a smell at all.