"Sweating" pipes and plumbing fixtures in summer-time
or during seasonal changes are not a sign of faulty plumbing. Due to condensation
of water vapor in the air, beads of moisture will form in warm weather
on any pipes and fixtures containing cold water.
Normally, when not in use, the water and fixtures
will worm rapidly to room temperature and the condensation will stop.
When a closet tank or other fixture continues to sweat for hours after
it has been used, it is a sign that cold water is continuing to flow through
it, possibly due to an improper adjustment of the tank valve or a leak.
Sweating pipes can be wrapped with an insulation material
which prevents the condensation and formation of moisture.