Toilet Sweat

Does a toilet sweat directly below the bowl (not the outside of the bowl, but directly below where you cannot see)? I've seen the outside of a bowl sweat, so my guess is the inside does as well, however I've never been able to witness this. Maybe this is the reason for there being rot of the floor materials around the flange.

Thanks,Bill

For it to sweat below the bowl, there would have to be air movement. If it is not well sealed around the flange, damp air could come up from below.

Most modern, low-flow toilets don't sweat unless they are used very frequently, you have very cold supply water, and, the humidity levels are fairly high. This is because the don't empty the tank when it is flushed, so the incoming water is partially mixed with the room-temperature water already in the tank. Since the bowl will contain some water from the last flush, it, too, will have tempered water.

If your set of conditions still has condensation, then you may need a tempering valve to supply warmed water to prevent condensation.

jadnashua said:

If your set of conditions still has condensation, then you may need a tempering valve to supply warmed water to prevent condensation.

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I installed a tempering valve when I built my house. My toilets never sweat regardless of how much use they get. I don't have A/C so the humidity in the house can be substantial. I've had to insulate the cold water lines, tank, softener, and iron filter to keep them from sweating.

If the hot water tank is too far away warm water would have trouble getting to the tank (even if it was only a hot water line to the tank).

molo said:

If the hot water tank is too far away warm water would have trouble getting to the tank (even if it was only a hot water line to the tank).

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Presumably the cold water line would be the same distance or further, so neither would be actually cold enough for it to sweat.

In fact, I deliberately plumbed the tempering valve so that both the hot and cold are being drawn from the far end of the lines where it is more likely to be tepid. It has the added benefit of the toilets never affecting the water pressure in the shower so as not to cause a scald condition.