# What's in a/c water? **URL:** \ **Category:** Factual Questions\ **Created:** [August 13, 2016, 5:01pm UTC](https://boards.straightdope.com/t/whats-in-a-c-water/762677 "2016-08-13T17:01:26Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [August 14, 2016, 4:36am UTC](https://boards.straightdope.com/t/whats-in-a-c-water/762677/21 "2016-08-14T04:36:16Z")
> [@nightshadea](#): > > What I meant about car water was like radiators ect … Absolutely not the same as, or even remotely similar to, condensate water from an air conditioner. First of all, it’s nearly always mixed about half and half with antifreeze. Even if it weren’t, it’s exposed to iron and aluminum at high temperatures and has a significantly different mineral content from what drips off of A/C evaporators. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [August 14, 2016, 5:49am UTC](https://boards.straightdope.com/t/whats-in-a-c-water/762677/22 "2016-08-14T05:49:24Z")
> [@beowulff](#): > > Strictly speaking, Legionnaire’s Disease was not caused by the bacteria in AC condensate, but rather the warm, stagnant water in a [cooling tower](https://en.wikipedia.org/wiki/Cooling_tower#Legionnaires.27_disease). > > Not to say that it couldn’t be in condensate, though. In the buildings we went through Legionella classes every year or so. On a yearly basis we would inspect the biological pads and replace as necessary. There have been cases of Legionnaire’s the were traced back to cooling coil condensate pans in the building’s HVAC cold deck. The water in a cooling tower is not stagnant it is continually pumped from the tower to the condenser and back to the tower. But the legionella can grow in the tower, the air being pulled through the tower can pick up some of the microbes. If the build supply fans pick up some of the air from the tower then it is pulled into the building. Then the microbes land on the cooling coils and drip to the bottom of the pan where they multiply. The air picks this concentration and delivers it through out the building. If the building has direct expansion oils then the same thing can happen if there are any microbes in the air coming into the building. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [August 14, 2016, 4:09pm UTC](https://boards.straightdope.com/t/whats-in-a-c-water/762677/23 "2016-08-14T16:09:43Z")
> [@HoneyBadgerDC](#): > > Madronna marsh which is right next to a large mall in Torrance ca was thinking of using condensed a/c water from the mall to keep the marsh wet in the summer months. I doubt there would be any danger there to the marsh. I would worry about metallic salts from the condenser surfaces, collector pans and piping. Any such that go into the marsh are going to stay there, and build up, year after year. Otherwise, a great “free use” idea like the radiators on Volvos that have ozone-destroying outer coatings. ---
**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:** [August 14, 2016, 4:59pm UTC](https://boards.straightdope.com/t/whats-in-a-c-water/762677/24 "2016-08-14T16:59:31Z")
> [@Amateur\_Barbarian](#): > > I would worry about metallic salts from the condenser surfaces, collector pans and piping. Any such that go into the marsh are going to stay there, and build up, year after year. Otherwise, a great “free use” idea like the radiators on Volvos that have ozone-destroying outer coatings. What do you mean? Iron and aluminum oxides? I’m pretty sure the marsh is full of those already. [Previous page](https://boards.straightdope.com/t/whats-in-a-c-water/762677.md?page=1)