Mould or Musty Smell in an RV: Find the Moisture, Clean Safely and Know When to Stop

Canadian RV owner’s repair guide · Educational information • Updated October 23, 2026 • About 4 minute read

A musty smell, black spotting in a cabinet or damp bedding in the morning all point to moisture. In an RV, a few litres of water in the wrong place can cause mould within days. This guide uses Health Canada advice to help you find the source, decide what you can clean yourself and know when to call a professional.

It covers small to medium mould on hard surfaces in an RV. It is not a substitute for medical advice.

Mould can irritate the eyes, nose and throat and can worsen asthma, with infants, children, seniors, pregnant people and people with respiratory conditions at higher risk. ^[1] Health Canada recommends a qualified professional for a single patch larger than 3 m², for mould that returns after cleaning, for sewage-contaminated water and for suspected mould inside walls or ceilings. ^[1] Do not use bleach to clean up mould. ^[1] If a wall or floor feels soft, stop and see the soft floor guide.

1. Find the moisture. Check roof and window seals, plumbing under sinks, the shower, the water heater area and the floor edges. Mould can start to grow within 48 hours in a damp area. ^[1] 2. Measure humidity with an inexpensive hygrometer. Health Canada recommends keeping relative humidity between 30 and 50 percent. ^{[1] [2]} 3. Look for condensation on cold surfaces, and use exhaust fans while cooking and showering and for a few minutes afterward. ^[2] 4. For small patches, wear safety glasses, a well-fitting N95 respirator and disposable gloves. ^[1] Clean hard surfaces with detergent and water, and throw out porous items that are mouldy. 5. Dry the area completely and run a dehumidifier if humidity stays above 50 percent. ^[1]

Small areas (three or fewer patches totalling about 1 m² or less) can be cleaned with precautions, and medium areas are often manageable at home. ^[1] Fix the leak before cleaning, since mould will return otherwise. Replace soaked insulation, carpet and cushions. Large areas, hidden growth or structural damage need a professional or a body shop.

Check the area again after a week and after the next rain or shower. Confirm that the smell is gone and humidity stays in range.

Cold walls and windows condense indoor moisture in winter, especially with propane cooking and several people aboard. Crack a vent, run the bath fan and keep bedding away from cold walls. For storage, empty the fridge, prop doors, remove damp items and use moisture control. Keep the roof sealed before rain and snow.

Before you book, send the component label, the RV year and model, the exact symptom and any displayed code, when it happens, photos taken from a safe position and the checks you have already completed. Mention recent repairs, freezing, impact or water exposure. Ask for a written quote in Canadian dollars that separates diagnosis, parts, labour, mobile travel charges and applicable taxes. The final cost depends on the confirmed fault, access and parts availability, so be wary of a firm price quoted before anyone has looked at the problem.

For this repair: If you hire help, ask for a written plan that addresses the moisture source as well as the cleaning.

These are original manufacturer or component-maker resources to help you find the instructions for your exact equipment. A manual for a named model is an example, not authority for every RV. Match the manufacturer, model and serial number before applying any procedure, and follow the matching manual where its details differ.

1. Health Canada: Addressing moisture and mould in your homeHealth effects, humidity target, cleanup thresholds, protective equipment and when to hire a professional.
2. Health Canada: Reduce humidity, moisture and mouldVentilation, exhaust fans, dehumidifiers and damp spots.

Reference links were selected on October 23, 2026. Manufacturers move and rename documents; if a link has moved, search the maker’s support site for your model number.