← Back to full guide | Tip: save it to your phone — the 60-second check takes less time than unpacking the swim bag

Pool Water Quality Checklist

Clear water is not the same as clean water — and a strong “chlorine” smell usually means the opposite of what parents assume. Run this check before anyone gets in, at any pool, hotel, or splash pad.

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🔍 The 60-Second Look Test

  • Can you see the main drain at the deepest point? If not, do not swim — cloudy water also hides a child on the bottom.
  • Is the water clear, not milky, green, or tinted? Haze means the disinfectant or filtration is losing ground.
  • Are the tiles and steps smooth, not slimy? A slippery film at the waterline is biofilm, which shelters germs from chlorine.
  • Is the pump running and are the skimmers moving water? Filtration has to be operating for the chemistry to mean anything.
  • Is there debris, film, or foam sitting on the surface? Untouched surface debris signals a pool no one is watching.

👎 The Smell Test — Read It Backwards

  • A well-run pool barely smells at all. Fresh chlorine is close to odorless in water.
  • A strong “pool smell” is chloramines, not chlorine. Chloramines form when chlorine reacts with sweat, urine, and body oils — it is a sign of too much contamination, not too much chlorine.
  • Indoors, that smell plus stinging eyes means poor ventilation. Chloramine gas collects at the water surface where children breathe.
  • Rinse in the shower before swimming. A one-minute rinse removes the sweat and oils that create chloramines in the first place.

🧪 The Numbers to Ask For (CDC)

  • Free chlorine: at least 1 ppm in pools. This is the working disinfectant — the number that actually kills germs.
  • Free chlorine: at least 3 ppm in hot tubs. Hot water burns off disinfectant far faster than pool water.
  • pH: 7.0 to 7.8. Outside that band chlorine works poorly and eyes and skin start to sting.
  • Ask when the pool was last tested and ask to see the log. A staffed facility should answer without hesitating; a hotel front desk that cannot is itself the answer.
  • Test your own home pool with a DPD kit, not strips. Test strips work but are noticeably less accurate.

🚩 Red Flags — Do Not Swim

  • You cannot see the bottom. This is a drowning hazard before it is ever a germ hazard.
  • Overpowering chemical smell or immediate eye and throat irritation. Leave the enclosure rather than waiting it out.
  • No one can tell you the chlorine and pH readings. Unmonitored water is unmanaged water.
  • The pump is off or the water surface is dead still. No circulation means no disinfection where it counts.
  • A closure sign is posted. A pool that closes itself is a pool being run correctly — respect it and come back later.

🚽 Don't Be the Source

  • Nobody swims with diarrhea — and stay out for 2 full weeks after it stops. CDC and the American Academy of Pediatrics both advise this, because Crypto keeps shedding after symptoms end.
  • Bathroom break every 60 minutes, whether or not anyone asks. Set a timer; children will not volunteer.
  • Check swim diapers every 30–60 minutes and change them away from the water. Swim diapers slow leakage — they do not seal.
  • Teach “don't swallow the water.” Nearly every recreational water illness starts with a mouthful.
  • Shower before getting in and rinse off after. Before protects the water; after protects your child's skin and ears.

💩 If the Pool Closes for a “Code Brown”

  • Formed stool: about 30 minutes. Staff net it out, raise free chlorine to 2 ppm at pH 7.5 or less, and hold it there for 30 minutes.
  • Diarrhea: hours, not minutes. A public pool operator raises chlorine very high for hours, because Crypto is extraordinarily chlorine-tolerant.
  • Why so long? Chlorine is fast for most germs, slow for one. At 1 ppm: E. coli under 1 minute, hepatitis A about 16 minutes, Giardia about 45 minutes, Crypto about 10.6 days.
  • Do not ask staff to reopen early. The clock is a disinfection requirement, not a courtesy delay.
  • A closure is a good sign. The pools worth worrying about are the ones that never close.

This Pool, Today — Fill This In

Pool / facility: ______________
Date & time checked: _________
Main drain visible? ___________
Free chlorine reading: ________
pH reading: _________________
Last tested (per staff): _______
Who I asked: ________________
Safe to swim? Y / N: __________

Created by WaterWiseKids.com — Free water safety education for families

Sources: CDC Healthy Swimming, CDC Model Aquatic Health Code, American Academy of Pediatrics

Back to the full guide · Why pools close for a code brown · Preventing recreational water illness

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A Well-Run Pool Is Part of a Well-Run Program

The same operators who test water on a schedule and close the pool when they have to are usually the ones running tight ratios and trained instructors. Water quality is one visible signal of how a facility is managed — and formal swim lessons reduce drowning risk by up to 88% for children ages 1–4.

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