How Often Does This Happen?
You don’t have to worry about evaporation occurring in the event of a weekend getaway or even a short business trip. In general, P-traps remain sealed for at least a couple of weeks, possibly even longer. However, in extreme circumstances, P-traps can dry up faster.
Extreme heat, dry environments, high levels of ventilation and/or air flow, and basement floor drains, laundry room standpipes and spare bathrooms tend to lose their water seal faster.
In most cases, this problem arises during longer trips, typically three weeks or more, or in areas of your home where the drain rarely receives water.
