If you pulled a gallon out of the air with the door closed, water is coming from somewhere else. A shower will not put that much water into the air.

Look for the real source of the problem

Unless there are trolls hiding in my walls, there's no way the water is coming from anywhere else, as far as I can tell... FWIW, the window AC unit is still in the window, so the rooms aren't exactly sealed.

Oh, and actually, it was more like 1/2 a gallon to 3/4 of a gallon. But still a lot of H2O.

I'll poke around the house to see if there's something I'm not seeing that may be a source of water.

-Z

Z,

If you are not sure, turn off the master water valve to the house for a day and see if there is any change. If there is, then there is a leak somewhere.

Do it on a weekday when fewer people are home and warn them about it beforehand. You get one flush then thats it until its turned back on.

Agree with James that this amount of water coming out of a machine is far too much for a shower. Possible 50 showers but no way with two people in a bathroom.

JA

Unless it a really long, super-extended shower, and them you'd better be pretty wrinkled and cold...

Yes, I've been drinking. So what.

And the problem is? Its dark somewhere in the world so prosit! :)

Ok - so now I'm getting more puzzled by this issue.

Last night, I bought one of those digital humiity gauges. The relative humidity in my bedroom was around 44%. Not too bad. After two showers, the level went up to around 50% - again, not too shabby. This was with the dehumidifier on. After an hour or so, the level went back down to low 40%'s. Again - pretty good.

At around midnight, I turned off the dehumidifier, and the relative humidity was around 42%. No more water was run that night - in the AM, the relative humidity read 60%! Still not too too bad, but it seems like quite a jump from the night before. What gives? (It came back down to mid-40's relatively quickly by running the dehum. for an hour or so.)

As others have said - there may be humidity coming from elsewhere - time to climb up into my attic and poke around....

And per the newsradio, the relative humitidy outside is around 48% this morning.

Still confused,
-Zoltan.

Just checked the attic above the bedroom -

Found a few water drop marks on the beams. But have they been there all along, and I didn't notice them cause I wasn't looking for them?

Felt the insulation above the area of the ceiling that has mold - the upper layer appears to be slightly damp, but the lower layers feel dry. It could simply be the cold - it's about 50 degrees up there.

I took my little humidity gauge up there, and it read a steady 41% - which is lower than the bedroom when the dehumidifier isn't running.

I will have to go back into the attic when it is raining and see if there is water coming through.

-Zoltan.

No bathroom should be without a good ventilating fan ducted to the OUTSIDE, not to the attic or crawl space. I have seen them ducted to a cold attic and whoopie!! When things warm up, signs of wetness on the ceilings and not just in the bathrooms.

Here in the South West our baths are generally in the center of the house, no windows (skylights), but each has a relatively high volume fan.

Additionally, once you find the problem and correct (either inside humidity or outside infiltration, remember the place that shows the damage can be feet away from the actual cause) and eliminate the mold, paint with a product that contains mildewcide. If it is necessary to replace wallboard, go with the new stuff that ha no paper covering. And seal the inside surface that faces the studs.

Been there. Done that.

RH - is just that, "relative" humidty. It is a measure of how much moisture is in the air relative to the maximum it can hold. Dew Point is a better way to look at how much moisture is around in absolute terms. Dew Point is a meaure of the partial pressure of moisture in the air. How quickly we forget our chemistry!

45 dry bulb (air temp) and 29 Dew point would be 42% RH, H20 PP .08 psi
70 dry bulb (air temp) and 50 Dew point would be 40% RH, H20 pp .178 psi
70 dry bulb (air temp) and 59 Dew point would be 61% RH, H20 pp .251 psi

So 40% RH inside your house at say 70 F is very different that 40% RH if the outside temp is 45 F. It will have more than twice the moisture.

If the temp in the room was constant, and the RH rose from 40% to 60%, there is moisture coming from somewhere, and a lot of it. It means that the amount of moisture in the air rose by 50% in a matter of hours. Keep looking for the source.

How does the water get to your baseboard radiators then? Also, do you have a crawlspace or a place where there is dirt under the house and no vapor barrier or are you on a slab?

fintstone: Underneath the bedroom is a garage. There is no crawlspace under the house - it is on a slab / concrete foundation.

And yes - I checked and didn't find any leak around the baseboard radiators - the pip runs alongside one wall - connecting to the bathroom. I will check that again though.

The temp in the room wasn't a constant - it did warm up by daybreak, probably 10 degrees or so.

And whenever I've turned off the dehumidifier, the humidity level would slowly (over hours) start to rise...

-Z

Yeah, Fint, I was thinking he might have a pipe in slab issue under the bedroom, but generally, NJ doesn't use slab foundations.

Z - How does the water get to the bathroom? Where are those pipes located?

red - per the diagram on page 1 - the pipes are located in the wall between the two bathrooms, not in the wall between the master bedroom and the master bath.

Is there a vent from the garage to the roof or is there a bathroom drain that goes in that direction? I had a leak (and wet spot in the ceiling) once and it came from the other side of the house. ran down a rafter. There was a nail driven through the wall that had hit a drain line so it fluctuated based on which sinks/showers were used.

I also had a shower pan once that leaked and the water seeped across the room under the tile and carpet and was wicked up into a wall by insulation. Strange stuff.

Perhaps an exorcist would help.