Effects of Chlorine in Swimming Pools (Properly Test) – WaterFiltersAdvisor

It’s summer vacation, you and your friends have just arrived in a beautiful resort. The sun is shining bright, the pool is clean and glistening. You jump in and almost immediately, you can smell the chemical stench of chlorine. You ignore it as you and your friends splash water amongst each other. Now, have you really thought about the effects of chlorine in the water?

Here, Water Filters Advisor will aim to answer the question as to why chlorine is added to water and whether or not it is safe for human beings.

What Is Chlorine?

First and foremost, what is chlorine? Chlorine is a naturally occurring element and a common substance on earth. Next, Chlorine is also one of the major pollutants in drinking water. A process called electrolysis produces chlorine from ordinary salt by passing it through the brine.

Adding Chlorine to Swimming Pool Water


Imagine what would happen if a group of people jumped into a pool together. Obviously aside from a big splash, bacteria would spread all around the water. Not only that but there are those (especially children) who take the opportunity to urinate in the pool since they think no one else is looking.

Urine is made up of many impurities including salt and waste products. 

why is chlorine added to pool water

The chemical stench you assume is chlorine when dipping into the pool isn’t actually chlorine itself, but a compound known as trichloramine. Trichloramine is produced when chlorine associates itself with sweat and urine.

Chlorine is added to the water,  which releases a weak acid called hypochlorous acid in order to kill bacteria such as E. coli and Salmonella. Germs that lead to viruses that can cause diarrhea are also killed. 


Many assume that too much chlorine causes irritation in the eyes. But, it is normally due to the buildup of urine and that not enough chlorine was added. However, over-chlorinated pools can negatively affect our hair and skin, causing it to dry out as well as causing visual irritation. That is why it is necessary to properly measure the levels of chlorine added to the pool. 

Generally speaking, you really shouldn’t worry about chlorine. Minor irritations can easily be washed off and catered to by applying moisturizer so that the natural oils that the chlorine may have stripped away come back.

Even if you don’t rinse off, nothing bad will happen to you. Sure, you may be left with brittle hair and dry skin, but that is about it. Nothing dire to worry about.

To avoid eye irritation, wear goggles. Another alternative is to use lubricating eye drops after you swim.

Testing Levels

testing chlorine levels in swimming pool

But how exactly do you measure the amount of chlorine added to a pool?  There are many ways to do so. Here are a few of them: 

Test Strips

Test strips are dipped into the pool and the color changes depending on the amount of chlorine added. After this, you compare the color of the strip to a chart that determines the level of chlorine. It only gives you the general idea of how much chlorine is added. However, test strips are not entirely accurate and that color change is subject to interpretation.

Using a Colorimeter

colorimeter is a type of light-sensitive chlorine test

A more reliable way of measuring chlorine is through a colorimeter. A colorimeter is a type of light-sensitive device that allows the absorption of a solution at a particular color of visual light to be determined. Using a colorimeter guarantees instant results as well as continuous testing.

Furthermore, with this method, it is unlikely to encounter human error since there is no need for the operator to perform visual analysis. That being said, maintenance of this method is highly necessary as well as the cost of chemical reagents.

Amperometric Method

low maintenance swimming pool chlorine testing

The amperometric method is a relatively new way of testing chlorine levels, and it is the most accurate out of all three technologies. Similar to the colorimeter, the amperometric method offers continuous testing though with less maintenance and it does not need to take samples like the colorimeter.

It also does not need the same chemicals that a colorimeter does. Therefore, this method costs less to operate. However, keep in mind that sensor probes may be initially expensive.

Bottom Line

Chlorine is a chemical that is highly effective when used to kill bacteria in our swimming pools and water systems. While we have discussed the potential hazards when it comes to the chemical itself, when used properly and in safe amounts, chlorine is very helpful.

With all the information above, you are one step closer to knowing everything you need to know about chlorine in your pool and how to test the levels.