Joi Ito's Web

Joi Ito's conversation with the living web.

I have a stupid question... Is there a risk swimming in a pool in a country where the water is not potable or does the chlorine basically "clean" the water?


i spent a few years working in wastewater, and some of my family members still work in wastewater.

its *probably* safe, as long as it is really chlorinated. you might bring along some of the little chlorine test strips i think you can get at pool supply places, and they will tell you how much chlorine is or is not in the water.

Biology can't stand up to chlorine. It's the main (post-filter) ingredient in making water potable.

My experience is most pools are overchlorinated if anything in foreign countries--sort of their liability measure. badmacktuck's test strips recommendation is a very good idea,

If you decide to relax in the hot tub after, that can be a different issue, you might want to check with the facility that they use bromine, as it lasts longer in higher temperatures than chlorine.

Some hotels have a dedicated water purification system for their swimming pools. I suspect that reputable hotel chains would have this.

Function only chlorine is only for disinfection (bacteria, algae) and not removal of any ions from the water. Not sure what you mean by clean.

The chlorine strips would help yes although I'm not sure what is the acceptable chlorine levels in swimming pools. In drinking water, it's usually 0.5-1.0 ppm. At 1 ppm onwards, you can smell the chlorine a bit and actually taste it in the water.

I'm just wondering if it is "safe" to swim in water in a country where they warn you not to drink the water. Often they will say not to eat fresh veggies washing in the water. I usually drink more pool water than that when I swim. I'm not going to drink glasses full of the pool water, but it will just end up in my mouth.

I suppose that if I can smell the chlorine, then it's "safe" even if it's not really "clean" then...

The chlorine may not "clean" the water, but there is no reason to worry about swollowing a few hundred thousand Magnesium or Calcium ions. :D

If you can smell "the pool smell", or the water burns your eyes, you should have no problems.

Note that chronic exposure to chlorinated pool water can erode your tooth enamel.

chlorine kills pretty much all bacteria, as far as i know

If you can smell the chlorine and the water looks clean I think your OK. One note on chlorine: I was a competitive swimmer in high school and developed an allergic reaction (rash) to chlorine over time. It subsided when I started swimming less.

Ah, if it's unsafe drinking water, it could be related to water-borne diseases which are usually caused by feces and urine in the water. In a lot of 3rd world countries, it's a major problems because of 1. public awareness and 2. lack of sanitary facilities available. In countries like these, the water is always boiled before drinking but it's not always a full-proof method. For people who have grown up in these countries, they build up a tolerance towards this but not so visitors from outside.

In the case of swimming pools, if you can smell the chlorine, you're alright. Chlorine is a strong killing machine against bacteria and viruses. Pool chlorine is usually NaOCl tablets / powder and note that this is the same as liquid bleach (the NaOCl) that is often used for disinfection in hospitals and contaminated area. Also, with pool chlorine always being overdosed, you should be fine.

Unless you observe what Steve Ross has mentioned but that's related to the chlorine in the water.

OK I need to stop the 'chlorine smell thing'. I was a pool director and am a Red Cross Water Safety Instructor. If a pool is properly chlorinated it will not smell or sting the eyes. The eye sting is from Chloromine - what happens when free chlorine 'reacts' organics like sunscreen.

If a pool has recently been 'Shocked' or super chlorinated you loose the eye sting and some of the smell. The best way to be sure is to see if there is a filtration / chlorination system. NEVER swim in a pool that is only standing water! I wish we could have gotten together in Austin - I could have certainly helped you with your stroke.

They probably add more chlorine which may be harmful in the long run but a dip or two should be ok.