What to do if…
you smell a strong musty odour and find mould spreading quickly after dampness

What to do now

1. Make a safer pause. Move to fresh air, another room, or outside. Close the affected room door if you can do that without staying in the room.
2. Check for water and electrical danger. If there is standing water or dampness near outlets, extension cords, HVAC equipment, or appliances, do not touch them. If you can do it safely, turn off power to that area at the breaker.
3. Stop the moisture source only if it is safe and obvious.
   • Turn off the nearest shutoff valve for a leaking sink, toilet, appliance, or pipe.
   • Use the main water shutoff if the leak is active and you know where it is.
   • If rain or storm water is coming in, move items away from wet areas and catch drips with buckets or towels.
4. Isolate the area. Keep the door closed. Open a window in that room if you can do it quickly and safely. Use an exhaust fan only if you know it vents outdoors.
5. Start drying without spreading mold through the home. Use a dehumidifier in or near the affected room if available. Keep airflow aimed within the affected area, not toward clean rooms. Try to dry wet materials within 24–48 hours where possible.
6. Move easy wet items only if this will not spread debris. Remove wet rugs, cushions, cardboard, and clutter from the area if they can be moved safely. Bag small moldy items before carrying them through clean areas.
7. Do not rely on testing first. A strong musty odor, visible mold, and damp materials are enough reason to act. The exact mold type does not need to be identified before fixing moisture and starting cleanup.
8. Protect yourself for brief entry. Wear gloves. If you must disturb dusty or moldy materials, wear eye protection and a well-fitting NIOSH-approved N95 or higher respirator.
9. Document and report right away.
   • Take photos or video of the mold, dampness source, water damage, and affected belongings.
   • Write down the date, time, room, smell, and what was wet.
   • If you rent, send a written report through the tenant portal, email, or text and keep copies. Ask what will be done to find the moisture source, dry the area, contain the work, and remove materials that cannot be cleaned or dried.
   • If you own, contact your homeowners insurance or emergency maintenance provider and ask whether emergency drying, mitigation, or temporary lodging may be covered.
10. Stop DIY and get professional help if the situation is bigger than a small surface patch. Get help if mold is in multiple rooms, inside walls or ceilings, under flooring, near or inside HVAC, caused by sewage or contaminated water, or affecting someone with asthma, allergies, immune suppression, chronic lung disease, or worsening symptoms.
11. Get medical help for breathing or severe symptoms. Call 911 for severe trouble breathing, chest pain, confusion, fainting, or blue lips or face. For milder symptoms that worry you, contact a clinician, urgent care, or your local health department for advice.