If your bathroom has an exhaust fan, always turn it on before you start the shower. Then, leave it on for at least 10-15 minutes after finishing the shower.  Venting out as much of the warm, humid air as possible will reduce the likelihood of tank sweat. Taking shorter, cooler showers will also help--and they're invigorating! Turn the fan on when you take a bath or run a lot of hot water in the sink as well. If your bathroom doesn't have a vent fan, crack open the door as a less ideal option. Opening a window won't help much unless the humidity is low outside. After finishing a shower, use a towel to quickly wipe away most of the water on the shower walls. You can also wipe the tub surface or shower floor. Then, take the wet towel somewhere outside the bathroom to dry out. If you don't do this, the water on the shower walls will evaporate into the surrounding warm air and condense on the cool toilet tank. Your first instinct on a hot day may be to open up the windows. However, if it is warmer outside than inside, and especially if it's both warmer and more humid outside, keep the bathroom windows closed. Otherwise, you're just increasing the temperature differential between the tank water and the air outside the tank, and providing moisture to condense on the surface. An air conditioner will bring the temperature of the air around the toilet closer to the temperature of the tank water. Likewise, either an air conditioner or a dehumidifier will reduce the moisture content in the air, which in turn reduces condensation. Central air conditioning or a whole-house dehumidifier should do the trick. In some cases, though, you may need to place a window A/C or a portable dehumidifier in the bathroom.
استعمل شفاط أو فتحة التهوية أثناء استحمامك. امسح جدران حمامك للتخلص من الرطوبة السطحية. أغلِق نوافذ الحمام خلال الأيام الدافئة عالية الرطوبة. شغّل التكييف أو جهاز إزالة الرطوبة في الحمام.