How to Test Pool Water the Right Way (and How Often)

By Imperial Valley Pool Services · Updated 2026-10-23

Test your pool at least weekly, more often in summer. A liquid drop test kit is more accurate than strips. Take the sample from elbow depth, away from skimmers and return jets, and test before adding any chemicals.

Pick a method

Test strips: fastest and cheapest. Good for a quick look, less precise.
Liquid drop kit (FAS-DPD or similar): the home standard. Takes a few minutes and is much more reliable.
Photometer or store testing: very accurate. Many pool stores, including Leslie's in El Centro, advertise in-store water testing. Call ahead to confirm.

How to take a good sample

Use a clean bottle or cup, rinsed with pool water.
Reach down about elbow depth, with the mouth upside down, then turn it up to fill.
Stay away from return jets, the skimmer and any place you just added chemicals.
Test right away. Chlorine and pH change as the sample sits in the heat.

When to test

Once a week as a baseline.
After a dust storm, heavy rain, or a big party.
After adding chemicals, once the water has circulated for several hours.
Any time the water looks cloudy, smells strongly of chlorine, or feels itchy.

Record the results

Write down each reading with the date. Patterns tell you more than any single test, like pH that creeps up every week or chlorine that is gone by evening. Our service reports show every reading from every visit, so you can see the trend.

Frequently asked questions

Why do my strips and the pool store disagree?

Strips are approximate and are affected by sunlight, moisture and timing. Trust the more precise test, and retest if the result matters.

Should I test in the morning or evening?

Pick a consistent time. Evening readings show how much chlorine the sun used up that day, which is useful in summer.