Testing and Recording Public Aquatic Water Quality

Public-facility testing is a schedule, not a single morning reading. The operator must know which parameters apply, how often each one is due, where to sample, what method is accepted, and what action follows a result.

Use the adopted code and permit first. The MAHC frequencies below are a national model for planning and comparison. They are not a substitute for your jurisdiction.

Why this matters

Water changes throughout the operating day. Sunlight, temperature, rain, bather load, contamination, aeration, source water, and chemical demand can move a result after opening. Automated control improves consistency, but probes measure one flowing sample stream. They do not replace every required independent test or bulk-water check.

The record must capture the real sequence. A number without a time, venue, method, correction, or retest cannot support a defensible operating decision.

Before you begin

Create a venue-by-venue schedule before opening. Include:

• operating hours and expected bather demand;
• manual or automated disinfectant feed;
• every independent recirculation system;
• required preopening and operating-day intervals;
• weekly, monthly, quarterly, and event-driven parameters;
• heated venue temperature checks;
• controller, ORP, flow, UV, ozone, or other required readings;
• extra testing after adjustment, contamination, equipment interruption, heavy use, or unusual weather;
• the person responsible for each interval and backup coverage.

Inspect the test kit. Confirm reagent identity, expiration, storage, sample-cell condition, instrument calibration, method range, and lighting. If the method cannot measure the expected value, obtain the correct test before relying on it.

Detailed procedure

1. Identify the controlling frequency

Read the permit and applicable regulation. Do not copy another property's schedule.

As a national model, the 2024 MAHC calls for disinfectant and pH testing before opening. It then describes different operating intervals for manual and automated feed systems, plus separate frequencies for alkalinity, hardness, CYA, saturation index, total dissolved solids, temperature, salt, and supplemental systems.

Record the actual local requirement in the facility plan. If the local rule is more frequent or adds a parameter, the local rule controls.

2. Select the sample point

Use the required in-line sample port when applicable. Sample each separate recirculation system independently. Label the sample by venue and system before moving to the next one.

The MAHC model also calls for a daily bulk-water comparison even when routine tests use an in-line port. For bulk water, it describes a representative point away from an inlet, below the surface, in an appropriate water depth, with rotated locations and periodic deep-area sampling.

Use Collecting and Testing a Water Sample for the physical sampling controls. Avoid returns, chemical feed points, make-up water, stagnant corners, and recently disturbed locations unless the procedure specifically targets them.

3. Test immediately

Run the required method without letting the sample sit in heat or sunlight. Measure disinfectant and pH using the approved DPD, FAS-DPD, comparator, photometer, or other accepted method. Follow exact fill marks, reagent order, mixing, wait time, endpoint, and test-range instructions.

Use Testing Free and Combined Chlorine and Testing pH, Alkalinity, Hardness, CYA, and Salt for the method details. This page controls the public-facility schedule and record, not the chemistry technique.

4. Record the result at the time of testing

Enter the actual result. Include the venue, sample point, time, method, operator, and any required equipment reading. Do not wait until the end of a shift and reconstruct a smooth series from memory.

Never replace an unexpected result with a retest. Record both and explain why the first result was challenged.

5. Compare the system evidence

At the same interval required by the facility plan, record and compare:

• independent disinfectant and pH;
• controller display and setpoints;
• ORP when used;
• water temperature;
• flow or turnover evidence;
• chemical feeder state and supply;
• relevant alarms;
• UV, ozone, or secondary-treatment state.

A stable controller can still be wrong because of probe fouling, calibration drift, sample-flow loss, air, chemical injection location, or a stale sample chamber. The independent water result decides whether further investigation is needed.

6. Act on an unacceptable result

Follow the facility's closure and correction procedure. Protect bathers first. Record the restriction or closure, then make only authorized adjustments using the exact label, manual, and approved calculation.

Allow adequate mixing. Retest with a valid method. Record the retest even when it still fails. Escalate equipment, contamination, feed, or authority problems instead of repeatedly adding product.

7. Complete the interval

Review the log for blank fields, impossible times, copied values, missing units, unexplained corrections, and overdue tests. Communicate the next due time and any increased monitoring requirement to the next responsible operator.

Model frequency reference

The following summarizes the MAHC model, not a universal legal schedule:

Use the source section and adopted local language before turning this table into a schedule.

Common problems

Handoff

State the latest valid results, unresolved disagreement, corrective work, venue restriction, and next due time. The next operator should not have to guess which number is current.