A strong "chlorine" smell feels like proof there is too much chlorine in the water. Usually it is the opposite.
The short answer: the CDC says that if you smell "chlorine" at a pool, you are probably smelling chloramines: chlorine that has combined with sweat, dirt and pee. TroubleFreePool: a strong chlorine smell typically means the pool is under-chlorinated for its stabilizer level. The fix is more free chlorine, not less.
Part of: Pool Chlorine: Types, Levels and How to Keep Them Steady, our overview of every chlorine question.
What you are smelling
Chlorine can combine with sweat, dirt and pee into irritants called chloramines (CDC). Chloramines can turn into gas and irritate the eyes and lungs (CDC). On your test kit they show up as combined chlorine: total chlorine minus free chlorine.
How to check
| Check | Means |
|---|---|
| Combined chlorine above 0.4 to 0.5 ppm | Chloramines: most health departments limit it to 0.4 ppm (CDC); TroubleFreePool acts above 0.5 ppm |
| Free chlorine below the target for your stabilizer | Under-chlorinated (TroubleFreePool) |
How to read the numbers: free vs total chlorine.
How to clear it
- Raise free chlorine. The CDC's operator advice: superchlorinate to 10 times the combined chlorine level. TroubleFreePool: if combined chlorine is above 0.5, use the SLAM process. Step by step: how to shock a pool.
- Keep it there. TroubleFreePool: if you keep free chlorine in the range for your stabilizer and proper pH, the pool should not smell like chlorine. See what chlorine level should a pool have?
- Cut what feeds chloramines. The CDC: shower before swimming; one minute removes most of the dirt on your body.
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Raises free chlorine Liquid chlorine (sodium hypochlorite)Sold as "liquid chlorine" or "chlorinating liquid". Check the strength (%) on the label: the dose depends on it. Shipping rules differ by product and state.
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Test kit A test kit that reads free and total chlorineFree chlorine and total chlorine are two separate readings. The CDC calls a DPD test kit the most accurate option for home pools; test strips are less accurate. Follow the kit's own instructions.
Sources
- CDC: Preventing eye irritation from pool chemicals (chlorine smell is chloramines, irritation, shower one minute)
- CDC: Chloramines and pool operation (written for pool operators) (0.4 ppm, 10 times rule)
- TroubleFreePool: Free chlorine and cyanuric acid relationship (smell means under-chlorinated, SLAM above 0.5)
- TroubleFreePool: ABCs of pool water chemistry (combined chlorine causes the smell)
Sources read on November 4, 2026. Product labels change: the label on the product you buy always wins.
