How often do you have to test a commercial pool, and what goes on the daily log

Who sets the testing schedule

There is no single national testing rule for commercial pools. State and county health departments write their own codes, and many borrow from the CDC's Model Aquatic Health Code (MAHC), which the CDC describes as voluntary guidance for the programs that regulate public pools. Its 5th edition was published in December 2024. California's code, for example, reaches the shared pools of HOA and condominium developments, with a separate record-keeping schedule for small ones.

This guide compares the MAHC with two state codes that spell out their logs in detail: California's Title 22 together with its Health and Safety Code, and Florida's rule 64E-9.004. The duty usually sits with the pool owner or operator. California's code addresses the pool operator directly, and Florida makes the daily record the responsibility of the owner or operator while adding that any able person can test the water and record it in the report. That person can be the service tech.

How often to test chlorine and pH

Every source requires at least one test a day. Under the MAHC, free chlorine (or bromine) and pH are tested at every aquatic venue before it opens each day. After that, the schedule depends on how the disinfectant is fed: every 2 hours while open for a manual feed system without an automated controller, and every 4 hours for an automated disinfectant feed system. In-line ORP readings, and water temperature for heated pools, are recorded at the same time as those tests.

California's Title 22 requires the pool operator to test disinfectant residual and pH at least once per day, and the temperature of heated pools daily as well. An automatic chemical monitoring system can perform the daily tests if the enforcing agency approves it and it is calibrated to the manufacturer's specifications.

Florida requires manually conducted tests for pH and disinfectant at least once every 24 hours. Its rule states that an ORP controller does not replace that manual daily test.

California has one notable exception. Its Health and Safety Code lets public pools in common interest developments with fewer than 25 units, such as small HOAs and condominium complexes, record the same information at least twice a week, no more than four days apart.

The weekly and monthly tests

The MAHC spreads the rest of the chemistry across a longer calendar. Total alkalinity is tested weekly. Calcium hardness, cyanuric acid and the saturation index are tested monthly, and total dissolved solids quarterly. Salt is tested at least weekly, or as the chlorine generator's manufacturer instructs, wherever in-line electrolytic chlorinators are used.

Cyanuric acid has two extra triggers in the MAHC: a test 24 hours after any CYA is added, and weekly tests when stabilized chlorine is the main disinfectant. Florida also asks for weekly CYA tests where chlorinated isocyanurates are used. California requires a monthly CYA test whenever the operator adds cyanuric acid, and asks for combined chlorine to be tested often enough to keep it below 0.4 ppm.

What goes on the log

California's wording is short and broad: a written daily record of all test results, equipment readings, calibrations and corrective action taken, kept at the pool site, plus separate records of CYA tests, combined chlorine tests, routine maintenance and repairs, and contamination or drowning incidents.

The MAHC lists what daily monitoring records should include, among them pH, disinfectant residuals, combined chlorine, pump and filter pressures or flow meter readings, CYA if used, equipment maintenance and malfunctions including calibration dates, water temperature for heated pools, the time of each filter backwash, calcium hardness, total alkalinity, the saturation index, any interruption of circulation, filtration or disinfection longer than an hour, and daily attendance. It also asks for a chemical inventory log that includes the expiration dates of test reagents.

Florida names a specific form, DH 921, the Monthly Swimming Pool Report, and allows a customized form as long as it contains the same information and is available to the department.

How long to keep the records

The MAHC asks facilities to keep operating records for at least 3 years and make them available to the health department on request. California's Title 22 requires at least two years, with the records submitted to the enforcing agency when asked. Florida's rule says the report is retained at the pool and made available to the department on request, without naming a period in that subsection.

The sources also agree on where the log lives: at the pool. California and Florida both put the records at the pool site, so keep the current log where the code says it belongs, not only in a truck or an office.

Common logging mistakes

Recording the reading but not the fix. California asks for corrective action alongside test results. A low chlorine reading with nothing written after it looks like a problem nobody handled.

Testing once when the code asks for more. A daily test satisfies California and Florida, but a jurisdiction that follows the MAHC expects tests every 2 or 4 hours while the pool is open, depending on how chlorine is fed.

Forgetting the CYA follow-up. Under the MAHC, adding stabilizer starts a 24 hour clock for a retest.

Filling in the sheet later. The codes describe a daily record of tests as they are made, and a week of entries written from memory at the end is not that. PoolRound's daily log mode for commercial pools keeps one dated line per day with the readings you entered, and exports the month as a PDF to print or file with the pool's records.

This guide is general information, not legal advice. Pool codes differ by state and county and change over time, and PoolRound does not certify that any log meets them. Check with the health department that inspects the pool.

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