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Accommodation – What are the signs of unhealthy water quality?


Now COVID restrictions have eased across Australia, there has been a real push to support the tourism industry. If you find yourself searching late at night for the best holiday destination and frantically locking in a 50% discounted flight deal, chances are you’ve caught the travel bug!


It’s pretty safe to say, that’s a bug most of us are happy to catch. However, chances are that’s not the only thing you can catch on that long-awaited trip away.


Some travellers either knowingly or not, have packed more than just the makeup bag and swimming trunks. Parasites, bacteria, viruses and other pathogens can also hitchhike their way to the swimming pool of your destination.


The Centre for Disease Control and Prevention (CDC), reported 493 recreational waterborne disease outbreaks were reported from 2000-2014- causing at least 27,219 illnesses and eight deaths.


Almost a third of those were traced to hotel swimming pools or hot tubs.


The major cause was by Cryptosporidium, a chlorine-resistant parasite. It can cause diarrhea, vomiting, nausea, and stomach cramps.


Legionella and Pseudomonas were also responsible for reported outbreaks. Legionella is a type of bacteria that causes Legionnaires’ disease. It results in flu-like symptoms and puts people at risk of severe pneumonia.


Pseudomonas is a common bacterium that can causehot tub rash” and “swimmer’s ear.”


So, who is at risk?

The answer is everyone, though there are those who are more susceptible than others. These include the elderly, pregnant women and children, all of which have weaker immune systems and therefore more likely to fall ill with infection.


What are the signs that the pool water quality is unhealthy?

As the water pathogens reported are all microscopic (not able to be seen with the naked eye), you won’t see them in and around the pool.


Most people look at a pool and see clear water and that is their indicator of ‘healthy water’. In fact, all that indicates is the clarity of the water.  It’s what you don’t see is what you should really be concerned about. Is it there? Or is it not there?


Another common mistake is thinking that the pool is safe if you smell ‘Chlorine’! Pure chlorine, that is used to sanitise pools has no smell. The ‘chlorine’ smell occurs when pure chlorine added to the pool combines with foreign matter (waste products), such as oils, body cells, hair cells, urine, fecal matter, sunscreen and much more. The resulting products are called chlorine by products.


One chlorine by product produced is called Trihalomethane gas. A gas so corrosive that it results in steel structures surrounding the pool rusting. So, you can only imagine what damage it does to our respiratory system. This is the ‘chlorine’ smell that is often identified be swimmers, either in the air, on the skin and hair or on the bikini and board shorts when you get home. You don’t have to be swimming to fall victim to illness, just simply present by the surrounds of the pool inhaling the gas.


So how do we really ensure that the water is healthy to swim in?

Well, firstly, if you smell ‘Chlorine’, turn around, head for reception and demand to know what Secondary sanitation equipment is being used to destroy these nasty water pathogens and chlorine byproducts. If the answer is “we only use chlorine”, know that chlorine as a sanitiser alone will not remove chlorine byproducts, they simply build up in concentration and as such cause more of a concern to the health of guests.


The answer you’re looking for is “we have secondary sanitation equipped to our pool/spa”. These are the following options of secondary sanitation system options available:

  • Ultraviolet light (UV)
  • Ozone gas
  • Advanced Oxidation Process (AOP), a combination of 1 & 2 above producing Hydroxyl Radicals, the most effective oxidizer of waste products and chlorine byproducts known in water chemistry.


These secondary sanitation systems also treat the water pathogens, such as Cryptosporidium (chlorine resistant).


Also know that according to CDC, chlorine alone is limited to the following kill times:

 Free Available Chlorine Germ-Killing Timetable
E. coli 0157:H7 (Bacterium) less than 1 minute
Hepatitis A (Virus) approximately 16 minutes
Giardia (Parasite) approximately 45 minutes
Cryptosporidium (Parasite) approximately 15,300 minutes (10.6 days)



  • Times based on 1 ppm free chlorine at pH 7.5 and 77°F (25°C)
  • These disinfection times are only for pools and hot tubs/spas that do not use cyanuric acid. Disinfection times are longer in the presence of cyanuric acid.

CDC, May 4, 2016.


Written by John Morrison BSc



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