Quick answer
A pool chemical log sheet is the daily record a commercial pool operator keeps of every water test: date, time, free chlorine, combined chlorine, pH, alkalinity, cyanuric acid, temperature, and any chemicals added. Health inspectors review it to confirm the pool stayed within code limits while open. Our free printable version covers all of these in one 31-line page.
- Record actual readings (e.g. "2.4"), never a checkmark or "OK".
- Test free chlorine and pH before opening and repeatedly while open — every 4 hours at minimum with an automated controller under the MAHC.
- Log every out-of-range reading together with the corrective action and a re-test.
- Keep completed sheets on site; inspectors can ask for past months.
What a pool chemical log sheet must include
Most state and county codes, and the CDC Model Aquatic Health Code (MAHC) they are increasingly based on, expect the same core fields. If your sheet is missing any of these, an inspector will usually note it:
| Column | Why it matters | Typical frequency |
|---|---|---|
| Date & time | Proves tests happened before opening and throughout the day | Every test |
| Free chlorine (FC) or bromine | Primary disinfectant — the #1 closure trigger | Opening + every 2–4 hrs |
| pH | Controls chlorine effectiveness and bather comfort | Opening + every 2–4 hrs |
| Total / combined chlorine (CC) | CC above 0.4 ppm signals chloramines | Daily |
| Total alkalinity (TA) | Buffers pH swings | Weekly (or per code) |
| Cyanuric acid (CYA) | Stabilizer; high CYA slows chlorine | Weekly / monthly |
| Calcium hardness | Protects surfaces and heaters | Weekly / monthly |
| Water temperature | Required for spas; affects demand | Every test |
| Flow rate & filter pressure | Proves turnover and circulation are working | Daily |
| Chemicals added / action | Documents your response to bad readings | As needed |
| Operator initials | Accountability for each entry | Every test |
How to fill out a pool chemical log correctly
- Fill in the header once a month — facility, pool name, month and pool volume. Inspectors match logs to specific bodies of water.
- Test before opening. The first line each day should be timestamped before the gates open.
- Write one line per test. Do not combine a morning and afternoon test on one line.
- Record the number, not a judgement. "1.8" is a record; "good" is not.
- Note the fix. If pH reads 8.0, write what you added and log the re-test on the next line.
- Initial every entry. If multiple staff test, initials show who was responsible.
Paper log sheet vs. controller printout
An automated chemical controller (ORP/pH) is a great tool, but most codes still require manual verification tests with a DPD or FAS-DPD kit logged by a person. Controller data complements your log sheet — it does not replace it. Keep the paper (or digital) log as the official record and note the controller reading next to your manual reading when they disagree.
Frequently asked questions
What should be on a pool chemical log sheet?
At minimum: date, time, free chlorine (or bromine), pH, combined chlorine, water temperature, chemicals added, and operator initials. Most commercial pools also track total alkalinity, cyanuric acid, calcium hardness, flow rate and filter pressure.
How long do I need to keep pool chemical logs?
It depends on your jurisdiction. Many codes require one to three years, and Wisconsin ATCP 76, for example, calls for two years. Keep the current season on site and archive older logs rather than discarding them.
Is there a free printable pool chemical log sheet?
Yes. The Commercial Pool Log PDF is free: it includes a 31-line daily pool chemistry log plus spa, safety checklist, maintenance, chemical inventory and incident logs. Enter your email to download it.
Can I keep a pool chemical log digitally?
Many health departments accept digital logs if they are available on site during an inspection and show who made each entry and when. Check with your local health department before retiring paper.
This page is an educational summary, not legal advice. Pool and spa codes differ by state and county and change over time — always confirm requirements with the health department that inspects your facility.