It’s the school summer holidays and parents across the UK are planning activities to entertain and exhaust their children.

Taking your little ones swimming is a great way to guarantee fun, and them being asleep by 7pm.

However if you plan to take a dip in a chlorinated swimming pool  it’s worth knowing what might be in it beside your children.

Chlorine in Swimming Pools Creates Toxic By-Products

In a study in Environmental Health Perspectives, chemists analysed exactly what was in chlorinated water from a public swimming pool.

They identified more than 100 chlorine by-products in the water. Many were toxic.


Chlorine by-products occur when chlorine reacts with impurities in the water.

Tests in a study published in Environmental Science & Technology, have shown that swimmers have detectable levels of a potentially dangerous chlorine by-product called haloacetic acids (HAAs) in their urine within 30 minutes of a swim.

The Environmental Protection Agency limits HAA levels in drinking water because high amounts may be linked to birth defects and cancer.

Researchers tested the urine of 49 volunteers who swam in or worked around an indoor and outdoor pool. The researchers found that HAAs appeared in the urine 20 to 30 minutes after exposure.

Worryingly, children were more likely than adults to have a high concentration of HAAs after swimming.

The top misconceptions about chlorine in swimming pools

1. Chlorine instantly kills germs


In fact, it can take up to several days for chlorine to fully kill germs in the pool. There are also germs today that are chlorine-tolerant and were not known to cause human disease until recently. Swallowing even a little water infested with these germs can make you very very sick.

2. The strong smell of chemicals in a pool means it’s clean

What you’re smelling is not chlorine.

The smell indicates that unhealthy chloramines have formed in the water. Chloramines are formed when chlorine combines with ammonia and nitrogen, which are released into the water by swimmers through sweat, wee, mucous and spit—all things children are excellent at creating.

Chloramines in the water can cause itchy eyes and even breathing problems. Some studies have shown that heavily chlorinated water can actually increase the risk of asthma among children.

Chloramines are not as effective as chlorine in sanitising a pool, and in fact leave less chlorine available to do its job.
It’s worth remembering that a properly disinfected chlorinated pool hardly smells at all.

3. It’s not that important to shower before getting in the pool

Couldn’t be more wrong!

We all carry healthy bacteria around on our bodies on a daily basis. Much of this bacteria is good in that it helps us create healthy immune systems. However, bacteria in our sweat and body oils isn’t always the healthy type, and whatever is on our skin when we jump into the pool jumps in with us.

4. You are not effected by the chemicals in a pool if you wear goggles and don’t swallow the water

It does limit your exposure, but the human body absorbs chlorine primarily through inhalation but also via the skin. At low levels, inhalation causes irritation to the skin and eyes along with a sore throat or a cough. At higher levels, it causes symptoms of asthma such as wheezing and tightness of the chest.

Indoor pools without proper ventilation place swimmers at a higher risk of chlorine exposure. They also increase the exposure to chloramines, which directly cause asthma when inhaled.

Younger swimmers are more susceptible to the effects because their bodies absorb the chemicals more readily than adults.

So what can you do?

There is no denying that swimming is great exercise so rather than boycotting it altogether, why not visit one of the UK’s chemical free public swimming pools.

Aside from the health benefits, swimming in chemical free water is a wonderful experience and leaves your skin feeling soft and clean.

If you really want to embrace the outdoors then there are plenty of wonderful wild swimming locations in the UK.  From rivers to natural plunge pools, there are an abundance of picnic worthy spots to spend a day.  Visit the Wild swimming website for ideas both here in the UK and abroad.






The World Today: New Study Warns Chlorine Bad for Asthma Sufferers The Negative Health Effects of Chlorine
New York State Department of Health: The Facts About Chlorine
Occupational and Environmental Medicine; Ecological Association Between Childhood Asthma and Availability of Indoor Chlorinated Swimming Pools in Europe; M. Nickmilder, et al.
Medicine and Science in Sports and Exercise; Assessment of Chlorine Exposure in Swimmers During Training; Franchek Drobnic, et al.