Do Pool Water Test Kits Expire?(A Close Look)

When winter has come and gone, days are warmer, and your family is keen to get back into the pool. The first thing to do is ensure that the water is chemically balanced, free of bacteria and algae, and safe for everyone to take the plunge. That means getting it tested or starting your home testing using a water test kit. If it’s been on the shelf all winter, will it still give accurate readings, or do pool water test kits expire?

Whether you’re using test strips or a liquid test kit, they both have a limited life span and will have an expiry date printed on their packaging. Even a digital water test kit will deteriorate over time as sensors become affected by harsh chemicals and may need to be recalibrated or replaced.

Balancing the chemistry of your pool water is not just about having a good-looking pool but also about the health of the people who use the pool. In this article, I’ll go through the three basic types of pool water test kits available and the pros and cons of each so that you can decide which is the best option. How long they last before they expire is one factor that will affect your decision.

Do Pool Water Test Kits Expire – And After How Long?

There’s little point in testing the water in your pool if the readings are inaccurate – you could be doing the chemical balance more harm than good. So, I’m going to take a closer look at what we’re testing for, each type of pool test kit, and how long you can use them before they expire.

What Does A Water Test Kit Need To Measure?

There’s more to healthy water than just seeing it sparkle in the sun – there’s a range of properties that make up a completely balanced pool. There’s no specific right and wrong, but these are the readings I use as the ideal chemical balance in my own pool:

pH: 7.2 – 7.6.

Chlorine: 1.0 – 3.0 ppm.

Total Alkalinity: 80 – 140 ppm.

Calcium Hardness: 200 – 300.

Cyanuric Acid: 25 – 50 ppm.

Total Dissolved Solids: 1000 – 2500 ppm.

What Are The Three Types Of Pool Water Test Kits?

While there are some variations and versions, there are three basic categories of test kits.

Pool Water Test Strips

Test strips are made of paper or plastic with pads that have been impregnated with chemicals that react to the various constituents in pool water. They can be bought separately for each test or as a multiple-test kit. Some strips will have, for example, four different tests on one strip: free chlorine, total chlorine, total alkalinity, and pH.


  • Strips are the most inexpensive way to test your pool.
  • They are easy to use – just dip them in the water and compare their color to the chart provided.
  • Results are immediate.


  • They are only as accurate as the user’s ability to compare colors – it’s been said that if you ask five people to do the color comparison, you’ll get five different results.
  • The strips will give an approximate result but not a specific reading.

What Is The Life Of Pool Water Test Strips?

Test strips should be stored in a dry place, in a sealed container, and away from heat. If this is done, they will last between 24 and 36 months before they start to deteriorate and can even be effective for up to 3 years. Unless you’ve bought them in bulk, you’ll use them well before they expire, and I suggest you use your supply of test strips within a year to be sure that they are giving accurate results.

Liquid Pool Water Test Kits

Liquid test kits used to be the standard method used by most homeowners to check the chemical balance of their pool water and are more accurate than test strips if used correctly. Plastic or glass vials are filled with pool water, and then a measured number of drops are put into each vial. The color changes are then matched to a chart to see the various chemical levels in the water.


  • These kits are more expensive than test strips, but they are still cheaper than sending samples to a laboratory for testing.
  • Used correctly, the tests are more accurate than test strips.
  • Results are immediate.


  • Liquid test kits are finicky to use. One extra drop, or one too little, and the resultant color change is an inaccurate guide to the level of a particular chemical.
  • The reagents can get contaminated easily, and if the vials are not thoroughly cleaned after each test, you’ll get inaccurate readings.

I think liquid test kits have become a little outdated, and the latest test strips are just as accurate and much easier to use.

What Is The Expiry Period For Liquid Test Kits?

Some reagents last longer than others, but generally, liquid pool test kits have an expiry date of one year. Carefully stored and kept sealed, this might extend to two years, but most manufacturers will have an expiry date on the containers, which should be adhered to if you want accurate readings.

Digital Pool Water Testers

Digital water testers use the latest technology to not only accurately analyze pool water but also store the information and, using Bluetooth connectivity, can send dosage instructions to your mobile phone.

The simpler digital testers analyze the colors on test strips, removing the human factor and providing a very accurate diagnosis of the water’s chemical health. Other more complex digital water testers have sensors that analyze the water either from a sample or by immersing electrodes just below the surface.


  • Accuracy is much greater than with manual testers, and digital testers are very easy to use.
  • Minimal amounts of reagents are required, making digital testers more environmentally friendly.
  • Results are obtained in seconds, and the process is simpler than using test strips or liquid test kits.
  • Digital testers can provide up to thirteen different readings, including Total Dissolved Solids (TDS), and record changes over time. This enables the pool owner to make accurate adjustments to keep the water healthy.


  • Digital water testers are initially more expensive, costing from around $250 to well over $1000.
  • Reagents are still required, which is an additional expense.

Do Digital Testers Have An Expiry Date?

Unlike test strips and liquid test kits, digital testers don’t have a specific lifespan. Still, they will need a certain amount of maintenance to continue to provide accurate readings. Many come with replacement sensors as these will become corroded eventually, and the testers may need to be recalibrated from time to time as they age.


Both pool water test strips and liquid testers have an expiry date ranging from one to two years, and it’s usually printed on the container. For accuracy, I recommend not using expired test kits, but if you’re testing your pool twice a week, you’re more than likely going to run out of strips or reagents before you run out of time. If you use a digital water tester, keep it well-maintained, and it will last indefinitely.