I owned a house with an indoor hot tub. It was built into a slate floor of a room that was about 13 x 13, off the master bath/closet area. It then opened onto a back screened-in porch. This was in Florida. The room could be completely closed off through a pocket door, and the hot tub had a cover that was always on unless we were in it/servicing it or unless it was empty. You could access the belly (bottom) of the tub through a utility/storage room underneath.

There was no mold problem at all. We just kept up with the chemicals. There *was* a chemical/pool smell if we were using it a lot and not keeping the pocket door closed, but only in the master bath (not even into the bedroom itself really). No special ventilation.

The best and only thing to do, in my mind, is to have a mold inspection clause in your contingencies...and hire a mold inspection company to come in and take a few air samples and test it. It isn't done on a normal home inspection. But, you can add it to your contingencies and hire it separate. It takes a few days to get results back.

My sister bought a house with a hot tub room and they had to tear out the floor and ceilings because of mold. So, I second the advice to get it checked out before purchase. Also, take a hard look at the windows in that room, because the extra humid air would probably lead to condensation on the glass which could rot out the frames.

Thanks for responses, I would be inclined to gut the room after purchase but I'm scared at what I would find....the mold contingency is a great idea--if they do find mold do any of you have any idea--is it something that would affect the whole house air quality or just that room/damaged areas. I'm thinking if one room in the house is infested with mold that those spores are in the whole house right?

"There was no mold problem at all. We just kept up with the chemicals."

The chemicals in the pool do not help with mold growth from the high moisture content produced in the structure around the pool.

For the most part the the water that evaporates and then deposits has been 'distilled' and is pretty clean, it just makes things wet.

Like I said - no mold problem at all. None. Whatsoever. I will say there is condition loosely known as hot tub lung that can cause respiratory problems for people who have had prolonged exposure to hot tubs. That did not happen to us, but I was aware of it and we were very careful to only run the tub when we were using it or to circulate things. When we found ourselves not using it for an extended period, we drained it and cleaned it out. If it just sits there as a tub of water and is not leaking/left bubbling away all the time, hot and open/what have you, it's not going to cause a mold problem. The house it was in was a complete custom build by the developer of the neighborhood, and there really were no problems other than when we had a pipe leak in the hot tub equipment room (for lack of a better term) underneath. Once that happened, we had a plumber create a custom containment system for any pipes that might leak in the future, with a vent to the outside to prevent disaster in case we weren't home or didn't notice what was going on. I think there is a potential for problems, but if you do the things you are supposed to do and don't do the things you're not supposed to do, you'll be fine, providing the room is well designed for the hot tub. This house was in Central Florida, so humidity and bathroom mold were issues if not dealt with, obviously.

I'm sure there are lots of scenarios that could cause disaster, but it's not like an indoor hot tub = automatic mold problem. I lived it for 5+ years and the house was 15 years old when we bought it. I would encourage you to look into the hot tub lung -- that is something that concerned us and we were very careful as a result.

To answer the question about mold remediation--
Yes, if there are spores in one room, it affects the whole house. The whole house must be thoroughly cleaned (after the mold/source is torn out). A mold remediation company will do this professionally, then take air samples for testing again, etc, until the samples came back clear. For a friend of mine (who did not have a hot tub in the house, just a small water leak in a wall), that took 3 rounds of "clean up" once the source was found, resolved, and repaired, before her air quality was fine.

Has anyone ever had an indoor hot tub and gutted the room? How much of a nightmare would it be to tear out? This particular home has tiled walls with a wood deck around the hot tub. I'm guessing like anything it could go ok or it could go terribly wrong.

"Like I said - no mold problem at all. None. Whatsoever."

You have no ideas unless you opened walls and sealed areas and looked in them, looked on the back of the ceiling from an attic or other access, pulled any access panels on the tub and looked in the concealed areas, etc.

You are just guessing.