or puddles

a skirting or a fixture

Thermo-hygrometer with relative humidity sensor:

and if you cannot

bromine dioxide

Tramex Water Damage Restoration Master Kit - WDMK-X US Products or puddlesTramex Water Damage Restoration Master Kit X WDMK X For evaluation and monitoring of water damage related moisture content and humidity in buildings WITH ACCOMPANYING BLUETOOTH APP The Tramex Water Damage Restoration Master Kit X is the topmost kit including the top of the range digital meters for moisture content and relative humidity testing and monitoring of ambient conditions, concrete, wood, tiles, drywall, plaster and numerous building materials