# Do public pools really have a chemical in the water that changes urine color? **URL:** \ **Category:** Factual Questions\ **Created:** [June 4, 2010, 2:45pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927 "2010-06-04T14:45:38Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![YogSothoth](https://avatars.discourse-cdn.com/v4/letter/y/8edcca/32.png) [@YogSothoth](https://boards.straightdope.com/u/YogSothoth)\ **Post date:** [June 4, 2010, 2:45pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/1 "2010-06-04T14:45:38Z")
After watching that “Grown Ups” movie trailer for I-don’t-know-how-many-times, I realize that rumors of this goes way back to when I was a kid and my parents used to take me out to public pools. People said back then that pools do that too, but I’ve never experienced it. Does such a thing really exist and is it really used widely in public pools nowadays? ---
**Author:** ![Dung\_Beetle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dung_beetle/32/7945_2.png) [@Dung\_Beetle](https://boards.straightdope.com/u/Dung_Beetle)\ **Post date:** [June 4, 2010, 2:46pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/2 "2010-06-04T14:46:40Z")
Not in any pool _I’ve_ ever peed in. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 4, 2010, 2:48pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/3 "2010-06-04T14:48:46Z")
> [@YogSosoth](#): > > After watching that “Grown Ups” movie trailer for I-don’t-know-how-many-times, I realize that rumors of this goes way back to when I was a kid and my parents used to take me out to public pools. People said back then that pools do that too, but I’ve never experienced it. Does such a thing really exist and is it really used widely in public pools nowadays? Grown Ups must have _LOVED_ you… ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 4, 2010, 2:52pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/4 "2010-06-04T14:52:39Z")
Likely not. [Wikipedia](http://en.wikipedia.org/wiki/Urine-indicator_dye) and [Snopes](http://www.snopes.com/science/poolpiss.asp) concur. This seems like something Cecil would’ve covered at some point, but I’m not seeing it. The main trouble I see is preventing your urine indicator from reacting with proteins in skin, or lady’s already skimpy bathing suits, with hilarious result. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [June 4, 2010, 2:54pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/5 "2010-06-04T14:54:00Z")
Yeah, I think it was snopes (not clicking on the link, too much popups) that said: Of COURSE there isn’t. If there were, the first thing kids would do is test the theory! ---
**Author:** ![Eyebrows\_0f\_Doom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eyebrows_0f_doom/32/3119_2.png) [@Eyebrows\_0f\_Doom](https://boards.straightdope.com/u/Eyebrows_0f_Doom)\ **Post date:** [June 4, 2010, 3:08pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/6 "2010-06-04T15:08:44Z")
Doesn’t the fact that you are \*asking \*the question show that of course it’s not true? Otherwise you’d have \*seen \*it and not have to ask if it happens. ---
**Author:** ![Renee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/renee/32/287_2.png) [@Renee](https://boards.straightdope.com/u/Renee)\ **Post date:** [June 4, 2010, 3:13pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/7 "2010-06-04T15:13:23Z")
Ha, I read that as public schools, not public pools, and thought _WTF_? ---
**Author:** ![AClockworkMelon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aclockworkmelon/32/10803_2.png) [@AClockworkMelon](https://boards.straightdope.com/u/AClockworkMelon)\ **Post date:** [June 4, 2010, 3:18pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/8 "2010-06-04T15:18:40Z")
> [@Renee](#): > > Ha, I read that as public schools, not public pools, and thought _WTF_? … ---
**Author:** ![boytyperanma](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)\ **Post date:** [June 4, 2010, 3:34pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/9 "2010-06-04T15:34:23Z")
I think the questions been answered. No there isn’t a chemical that can do that. The next question is what interest would a public pool have in using such a chemical anyhow? Embarrassing some children not to pee in the pool sounds like a poorly thought out concept. Some children would be peeing in the pool anyhow and some might be encouraged to do so by the dye. Now you have a dye spot in the pool. What happens next? everyone runs in terror? Close the pool till it dissipates? Drag the offender over the the gallows? ---
**Author:** ![Clark\_Cello](https://avatars.discourse-cdn.com/v4/letter/c/58f4c7/32.png) [@Clark\_Cello](https://boards.straightdope.com/u/Clark_Cello)\ **Post date:** [June 4, 2010, 3:35pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/10 "2010-06-04T15:35:56Z")
I’m not real proud of this, but from the age of about 6 to about 16 I peed in just about every pool I was ever in. If there is such a thing, it is in very limited use. ---
**Author:** ![needscoffee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/needscoffee/32/1076_2.png) [@needscoffee](https://boards.straightdope.com/u/needscoffee)\ **Post date:** [June 4, 2010, 4:20pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/11 "2010-06-04T16:20:21Z")
Need to know quick? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 4, 2010, 4:24pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/12 "2010-06-04T16:24:54Z")
They could make everybody eat broccoli before entering the pool. ---
**Author:** ![Shark\_Sandwich](https://avatars.discourse-cdn.com/v4/letter/s/f04885/32.png) [@Shark\_Sandwich](https://boards.straightdope.com/u/Shark_Sandwich)\ **Post date:** [June 4, 2010, 4:35pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/13 "2010-06-04T16:35:09Z")
We played a prank on some of our friends when we had a pool party that there was such a chemical. My wife set it up perfectly. While sitting around, some of my friends and family started talking about our pool, how tough the maintenance on it was, etc. My wife laid it out perfectly and told them that there was in fact a new chemical that turned blue in the presence of urine. Some people believed it immediately, some claimed they’d heard it was just an urban legend. About an hour later, the steaks are on the grill, and the beer and margaritas are still flowing. Acting a bit more tipsy than I actually was, I tell everyone I’m gonna run in and change into my baggies for a quick dip before we eat. Put a little food coloring vial in my pocket, came back out, and with a beer in my hand walked into the pool, and just kinda meandered around in waist-deep water. Without any fanfare, I cracked open the food coloring vial, and was quickly surrounded by a nice blue “cloud.” Some people who were in the pool, immediately scrambled to get out, but most just laughed their asses off. ---
**Author:** ![RedSwinglineOne](https://avatars.discourse-cdn.com/v4/letter/r/a9adbd/32.png) [@RedSwinglineOne](https://boards.straightdope.com/u/RedSwinglineOne)\ **Post date:** [June 4, 2010, 5:29pm UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/14 "2010-06-04T17:29:25Z")
[Lifeguard pees in the pool.](http://www.youtube.com/watch?v=qLZY2AW8EfI) ---
**Author:** ![Ionizer](https://avatars.discourse-cdn.com/v4/letter/i/5daacb/32.png) [@Ionizer](https://boards.straightdope.com/u/Ionizer)\ **Post date:** [June 5, 2010, 12:57am UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/15 "2010-06-05T00:57:10Z")
> [@ed malin](#): > > They could make everybody eat broccoli before entering the pool. Or maybe even asparagus! 🙂 ---
**Author:** ![Guinastasia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guinastasia/32/5751_2.png) [@Guinastasia](https://boards.straightdope.com/u/Guinastasia)\ **Post date:** [June 5, 2010, 1:10am UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/16 "2010-06-05T01:10:06Z")
Perhaps if you had some methalane blue…but would that show up in the water? ---
**Author:** ![LouisB](https://avatars.discourse-cdn.com/v4/letter/l/dfb087/32.png) [@LouisB](https://boards.straightdope.com/u/LouisB)\ **Post date:** [June 5, 2010, 1:31am UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/17 "2010-06-05T01:31:03Z")
I’ve offered to wager considerable sums on the outcome of color changes in water as a result of my peeing in swimming pools; I’ve yet to have anyone take the bet. PS: I’ve also offered to cover the cost of draining and refilling the pool, provided the wager exceeded the cost. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [June 5, 2010, 5:45am UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/18 "2010-06-05T05:45:59Z")
Urine is over 95% water. I’d think it would be hard to come up with a reasonably-priced chemical that could differentiate the other 5%, especially given that it’s about a cup or two within the thousands of gallons of a typical swimming pool. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [June 5, 2010, 10:52am UTC](https://boards.straightdope.com/t/do-public-pools-really-have-a-chemical-in-the-water-that-changes-urine-color/541927/19 "2010-06-05T10:52:30Z")
> [@t-bonham@scc.net](#): > > Urine is over 95% water. I’d think it would be hard to come up with a reasonably-priced chemical that could differentiate the other 5%, especially given that it’s about a cup or two within the thousands of gallons of a typical swimming pool. The thousands of gallons of the pool are irrelevant. When the urine is first released, it is concentrated in a small area. An indicator of some kind probably is possible - what is impractical is finding one that: [ul] [li]Doesn’t react with other things such as sweat[/li][li]Isn’t toxic, irritant or otherwise dangerous to humans[/li][/ul]