Read Article

Tuesday, October 30, 2018
The Smell of Chlorine?
by Cynthia Osborne 

A question came up recently about the “smell of chlorine’ in the hallway entering the pool of the facility where I teach.  So, I put together some information to share with my class and now many recognize the benefit of following the posted pool rules!

That smell is actually a chemical reaction that takes place when chlorine (chemical used to treat the water) combines with ammonia (found in sweat and urine) or with nitrogen-containing contaminants to create chloramines. Both occurrences are common but can be minimized if pool patrons follow these pool rules:

  • Shower with soap and warm water to remove lotions and creams before entering the pool.
  • Wash hands after using the toilet.
  • Avoid the pool if currently have or recently (within 2 weeks) had diarrhea.
  • Wear a bathing cap while swimming.


Additionally, there are rules that the pool maintenance staff must follow. It is imperative they monitor and maintain effective levels of disinfecting chemicals, circulation (air and water), and water pH balance at all times. Chloramines are the cause of the “chlorine-like smell” associated with indoor pools.  These gasses are volatile and will evaporate and they may dissolve back into the pool water.  As a result, it is important to replace pool air with fresh outside air to remove chloramines.  The return air vent in the pool is designed to remove air from the surface of the water.  Closing the pool doors helps prevent air that is laden with moisture and chloramines from migrating into adjacent areas, such as the locker room and hallway.  When air temperatures are maintain 2-5 degrees (1-2.5 C) above water temperature, evaporation of pool water is minimized helping reduce chloramine concentration – plus participants in the water won't feel chilly.  Also, adding fresh water to the pool reduces the concentration of chloramines.

As an instructor or personal trainer, you are most likely not responsible for maintaining the pool chemicals.  However, when any strong or unusual chemical smell is noticed, you should alert staff who are monitoring the pool.  It may be a simple fix of opening an outside door, turning on the fan, adding water, or calling pool maintenance.  And, by following simple pool rules, our class participants can take an active role in minimizing the “smell of chlorine”…which we now know is actually chloramines!


National Swimming Pool Foundation Pool & Spa Operator Handbook.  2011 Edition. Pages 44, 45, 49, 74, 76, 158, 159.


Cynthia Osborne is the owner of CJOsmiles Aquatics.  She hold multiple certifications and trainings in the industry including: AEA Aquatic Fitness Professional Certification, AEA Arthritis Foundation Program Leader, AFAA Group Exercise Instructor, WITS Personal Trainer, American Red Cross (lifeguard, WSI, CPR/AED), Hydrorider Diamond AquaJump, and BioExercise.

Join our mailing list »