Location and weather are clues
Record whether moisture appears after rain, snowmelt, humid weather or plumbing use.
Moisture control comes before cosmetic repair
Painting over staining does not address the water source.
Contaminated water is a separate hazard
Sewage or floodwater contamination changes cleanup and professional requirements.
Avoid one-product diagnosis
Interior coatings, drainage work, grading, plumbing repair and dehumidification solve different mechanisms.
Safety boundary. General planning information only. Do not open, dismantle or work on hazardous electrical, gas, structural, fire-protection or contaminated-water systems unless you are appropriately qualified and authorized.