The main reasons people get sick from pool water: Too little sanitizer, improperly balanced water, poorly filtered pool water, and poorly circulated pool water.

While the CDC (Center for Disease Control) cannot do a whole lot about the latter reasons, it does want to help pool owners learn how to properly test for free chlorine residual in their pool water.

On this page on the CDC web site we found the following instructions for practicing free chlorine testing at home:

Testing the strips at home before visiting the pool can help you learn how to properly use and read them.

In order to test at home, you will need:

  • 3 containers
  • 13 cups of regular tap water
  • 3 drops of liquid chlorine bleach *please note that if bleach is more than 3 months old, it may be too old to provide an accurate test

Allow tap to run for about 2 minutes

  • Fill container 1 with 1 cup of water
  • Fill containers 2 and 3 with 6 cups of water each
  • Add 1 drop of liquid chlorine bleach to container 2
  • Add 2 drops of liquid chlorine bleach to container 3

Test each container of water utilizing the strips and the manufacturer’s instructions and compare your results to the values below:

  • 0 to 1 ppm free chlorine expected
  • 2 to 3 ppm free chlorine expected
  • 4 to 5 ppm free chlorine expected

Many people assume they know how to use their pool test strips because the instructions seem so simple and easy to follow but in reality a good number of pool owners perform pool water testing incorrectly. also, a good number of pool owners use out-of-date reagents and test strips. A definite no-no if you want to get accurate test results!