I know where the leak originated, and that has been corrected. My question is whether the portion of the ceiling below(drywall) that got wet should be remudded, sanded and painted OR replaced. How does one know if the leak caused mold on topside of the drywall where you can't see unless you cut into it? I don't know if I should believe the builder who says that the leak wouldn't have caused any mold...

Depends on how long the leak was there. Months? Probably have some mold. Couple of days, probably not. Use an ice pick to test the spot. If the drywall is still hard, just retape and mud. If soft, cut it out and put in a patch.

When moisture goes away, mold goes away

I can't ever remember not agreeing with both of you but I have a totally different read on mold. Mold spores are everywhere and once a surface is wetted to above 60% humidity the spores will germinate. When moisture levels drop and the mold can no longer grow it goes dormaint waiting for the next sign of dampness, then the spore regerminate. So GA how long was the drywall damp? http://www.fastmoldremoval.com/facts-about-mold-236.html

I don't know if I should believe the builder who says that the leak wouldn't have \aused any mold.. Your builder's blowing smoke up your skirt. Of course moisture promotes mold. What's going to help you is the AC. It acts as a dehumidifier and will dry out the ceiling drywall. Is it dry now? Back to you, Tom

Bob, are you also disagreeing with you own referance material?

FACT: Mold's function in nature is to break down and decompose dead organic material. This leads to the odor associated with mold.
FACT:Mold is always in the air around us naturally both inside and out, the only way to control indoor mold growth is to control the indoor moisture.
FACT: Mold spores are extremely tiny and float through the air. They can maintain their viability to reproduce in many environments until they land on a appropriate surface.
FACT: If the air is sufficiently humid over a sustained period many molds can get their moisture requirements to grow from the air. This makes basements and attics especially susceptible.
FACT: If mold is a problem in your home you must clean up the mold and eliminate sources of moisture, without sufficient moisture the mold cannot grow.

Good points but the last fact is what I hang my hat on "FACT: If mold is a problem in your home you must clean up the mold and eliminate sources of moisture, without sufficient moisture the mold cannot grow." Once mold has germinated it is much more problematic than spores floating in the air. Can't really say much more since GA seems to have not returned to answer my question about how long the leak was active. I am thinking the builder just doesn't want the trouble/expense/labor of taering out the moldy drywall and replacing it.

Wet for maybe a week. Spots that were wet (along seam over to wall) can now be seen through the "mud" that builder put up. It has not been sanded or painted yet. My son had an asthma attack within 2 hours of being in house for 1st time, I have not been feeling well since I am back in town (two weeks now). Im not full time resident of home yet. I am guessing that it is not a good sign to be able to see the bubbled spots through mud... I am feeling like I should insist that builder take out a piece to see of there is mold on other side. Is that what you would do?

Yes, a fairly large piece should be removed. Normally patches are cut to open a joist or rafter cavity sothe new drywall can be attached to studs or joists.

Thank you for your help. I truly appreciate it. Both my sons have told me to not just let them patch and move on.. but I wanted to get info from others and you have been helpful. The portion of the drywall that was wet ran along the entire seam (stud) of where two 4x8 pieces of drywall in the ceiling met, and then down to the wall which also appeared to be on a seam. I am guessing (being absolutely ignorant with regard to this type of thing) that this may be because a crack (seam) is where water will find its way out unless it is so much water that the whole piece of drywall sags and collapses. A seam of two pieces of drywall is only covered by tape and mud, so it would be the most likely place for the water to show, right? Wouldn't they need to remove those two pieces of 4x8 drywall since there would be no place to reattach a patch if they just cut the drywall all along the seam (stud) that got wet? Im not looking for a bigger job than necessary, but I want to be darn sure that there is not a problem that will only get worse with time. Basements tend to be damper than the rest of the house and I am not going to run my a/c at 76 degrees when I am not even in the house. I have it set at 84 when I am gone. I would think that is where we start and if we find mold, then we work our way over to the wall...