Swimming Pools are Clean, Are You?

Swimming Pools are Clean, Are You?
As a blogger for all things pools, I have my eyes and ears open for interesting swimming pool news. On a daily basis, I comb the internet for interesting tidbits, stories of exotic animals in pools, cannonball contests, and useful maintenance tips. As such, I have to wade through sometimes hyped-up warnings regarding the dangers of germs in pools, causing RWI’s.


If you are unfamiliar with Recreational Water Illnesses or RWI’s, the most common examples are diarrheal illnesses (spread by swallowing contaminated water), rashes, swimmer’s ear, eye infections, respiratory infections, or infected wounds. The Kingpin Germ Villain today is ‘Crypto’, or Cryptosporidium, and it even sounds menacing.

If you didn’t know any better, a quick Google search would lead you to believe that pools are summer’s biggest menace. In fact, I just read a 4-page article that served up 3.5 pages of all the horrible germs and diseases that await us all if we go in the water. The article ended abruptly with a short list of bulleted tips:

• Don’t use your pool as a toilet
• Don’t let other people use a pool as a toilet
• Don’t use your pool as a bathtub, be cleanNick Cage - "You Don't Say!" meme
• Don’t swim in the pool if you have diarrhea
• Don’t drink your pool water even if it is not being used as a toilet

This is pretty basic stuff. Let’s put things in perspective:
There is another place that has a similar set of rules: the kitchen. According to the CDC, 1 in 6 Americans, or roughly 48 million people, get sick from food poisoning caused by similar germs and bacteria. That’s a lot of people.

There are an estimated 10,000 cases of RWI’s annually, and that number in recent years has admittedly been increasing. Thankfully, the internet isn’t awash in reports and warnings from Mommy Bloggers about the dangers of going to restaurants. Or maybe there, are…do poor reviews count?

Q: Who Do We Blame? A: The Children!
Let’s face it, children are gross little disease-spreading creatures that ruin all the adults’ fun. But there is hope for them yet. It’s important to take smaller children on regular bathroom breaks while swimming and for even smaller children it’s necessary to change their diapers in a proper changing area. You wouldn’t change a diaper on the kitchen counter, so don’t do it by the pool.

Above all, kids and adults should shower after a #2 visit to the bathroom.The pool isn’t a toilet and isn’t a bathtub either. We all joke about peeing in the pool and this lighthearted humor could mask the the importance of personal hygiene especially in the water. Educate first, and then tell the peeing in the pool jokes.

Does Chlorine Effectively Kill All the Germs in a Pool?
The short answer is yes, but some germs are tougher than others. Crypto and Pseudomonas for example, can survive in a properly chlorinated pool. That is why shocking the pool regularly is important, that’s why we do it – to kill bacteria that escape our normal disinfection.

If you are a reader of the In The Swim Blog you hear us repeatedly stress the importance of testing your water as frequently as possible. However, sanitary pool water requires much more – a clean pool, with proper water balance, daily circulation and filtration, a daily sanitizer and regular oxidation (pool shock).

What are the proper pH, Alkalinity and Chlorine Levels for a Pool?

Chlorine Vs. Bacteria cartoonUse a good test kit or test strip that can test all of the important parameters. I like the Taylor K-2005.

  • pH: 7.2-7.8
  • Total Alkalinity: 80-120 ppm
  • Calcium Hardness: 200-400 ppm
  • Chlorine Levels: 1.5-3 ppm
  • Chlorine Stabilizer: 20-50 ppm

When and How Often Should I Shock My Pool?
It’s best to shock your pool in the evening because the sun’s UV light destroys the strength of chlorine. Keep your filter running overnight if possible. Be sure your pH level is correct, or a bit on the low side (7.2), so that the shock oxidizer works most effectively.

  • After a pool party or heavy use
  • At pool start up of for algae treatment
  • After extended periods of heat
  • After heavy rains or leaf litter
  • If there is a strong odor of chlorine
  • If the water appears cloudy or dirty
  • If a raccoon gets into your pool (seriously)*

We already covered that people carry germs but extended periods of hot weather can consume sanitizer, and heavy rains or flooding can flush contaminants into your pool. If you smell a strong odor of chlorine in the pool, this usually means that there is a build-up of chloramines in the water. This can be tested and confirmed with a DPD test kit.

*While most little critters found in the pool are typically harmless raccoons are not. The CDC warns that, “Raccoon feces can sometimes contain the eggs of a worm called Baylisascaris procyonis, which can infect humans, particularly children, and cause neurological illnesses.“

How much Pool Shock to Use?
I consulted with Dr. Pool on this one, and his first response was “it depends”. That is, it depends on what type of issue you are trying to solve.

  • Cloudy Water – 10 ppm
  • Chloramine Removal – 10 ppm
  • Algae Treatment – 10-30 ppm “depends on severity
  • Bacteria Removal – 10-30 ppm “depends on strain“*

*He means “strain” of bacteria. For those “pathogenic bacteria“, ones that make us sick, Dr. Pool says to “shock to 30 ppm“. Use 1.2 lbs of of Pool Shock, or 1.0 lbs of Super Shock, to raise chlorine levels to 10 ppm, per 10,000 gallons of pool water. Or more simply, to reach 30 ppm, use 3-4 lbs of pool shock, per 10,000 gallons “with a suitably low pH“.

In The Swim’s colorful infographic on How Often and When to Shock a Pool

Hungry, Hungry Enzymes: How Do Enzymes Work in Pools?
An unsung hero of the pool sanitizer world are enzymes. Pool Enzymes help make chlorine stronger by essentially eating-up non-living organic materials which turns the byproduct into water (it’s cool if enzymes pee in the pool) which clears the way for chlorine to come through and kick out the troublemakers.

In The Swim also made this equally colorful Pool Enzyme Infographic.

Are Saltwater Pools Better Sanitized Than Chlorine Pools?
It’s a trick question. A Saltwater pool is still disinfected with chlorine. The salt doesn’t disinfect, the salt chlorine generated from a salt cell uses electrolysis with the salt to produce hypochlorous acid (HClO) and sodium hypochlorite (NaClO) which is a fancy way of saying “chlorine”. So no, salt systems are not more effective than chlorine tablets or liquid chlorine.

Don’t Believe the Hype:
If a pool is properly balanced, if your swimmers are clean, and you don’t make a habit of drinking pool water you really have nothing to worry about. It is important to educate yourself and children about the potential to get sick from dirty pool habits, and protect your guests, family and self from potential disease-causing bacteria and germs by sanitizing your pool the right way – Constant and Consistent, with regular super-chlorination or shock treatments.

One more great graphic from the CDC about Healthy Pool Water


Ryan Dornan
InTheSwim Staff Blogger



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