Mold in an RV: What Cleaning Fixes and When It's a Leak

Is it mold or mildew in your RV?

Mildew is a flat, powdery growth. It looks gray or white and sits on top of a surface. You often see it on vinyl, window frames, shower walls and fabric.

Mold looks fuzzy or slimy. It can be black, green, blue or white. On soft things like foam, wood and wall board, it can grow down into the material.

Both are fungi (tiny living things that grow from spores floating in the air). Both need damp that sticks around.

Black mold in an RV looks scary. But color alone does not tell you the type or how bad it is. Handle all mold the same careful way.

Where does mold hide in an RV?

Mold grows where damp air meets a cold surface. It also grows where a slow leak keeps things wet. Check these spots first.

• Under the mattress, where body heat meets a cold bed platform all night.
• Behind cushions and inside cabinets that sit against outside walls.
• Around windows, in the corners and along the bottom of the frame.
• Near roof vents, skylights, the AC unit and the bunk over the cab.
• Under sinks and around the toilet, where small plumbing leaks hide.
• In slide-out corners, along the rubber seals and on the floor under the slide.
• In the shower, closets and any spot where wet towels or gear pile up.
• Outside on the awning fabric, if it was rolled up wet. That needs its own cleaning steps.

Why do RVs get moldy in the Bay Area?

The Bay Area is mild, but it is damp in the right places. Near the coast, summer fog and the marine layer can keep a parked rig wet for days. Think of the Sunset, Pacifica, Half Moon Bay and Sausalito.

The rain season runs from about fall into spring. That is when a tired roof seam or window seal starts to leak.

Many rigs sit for months in a driveway, side yard or storage lot. A shut RV warms up in the afternoon sun, then cools fast at night. The damp air inside turns to water drops on the cold walls and windows.

How can you tell if RV mold means a leak?

A leak leaves a trail. Look for stains that run down from a window corner, a vent or a roof seam. Press on the walls and floor near those spots. Soft, spongy or bubbled panels mean water has soaked in.

Watch for delamination too. That is when the outer wall skin comes loose from the wall behind it. It shows as waves or bubbles on the outside of the RV. It usually means water got inside the wall.

How do you get rid of mold in an RV safely?

Only DIY small, surface patches on things you can scrub or wash. The EPA says most people can clean a moldy patch smaller than about 10 square feet. That is roughly 3 feet by 3 feet.

Follow the EPA mold cleanup guide (epa.gov/mold) for gloves, eye protection and the right mask. If you have asthma, allergies or other breathing problems, let someone else do the job.

• Open the door, windows and roof vents. Set a fan to blow air out a window.
• Put on gloves, eye protection and a mask from the EPA guide.
• Bag loose bedding, towels and clothes, and carry the bags outside. Take them straight to the wash.
• Scrub hard surfaces with a mild detergent and warm water. Use a soft brush on textured walls.
• Wipe with a clean, damp cloth. Then dry each spot right away with a towel.
• Wash fabric covers on the hottest setting the care label allows.
• Run a fan or a dehumidifier (a machine that pulls water out of the air) for a full day.
• Check the same spots in a week. If the mold is back, look for a leak.

What should you never do when cleaning RV mold?

These common moves make mold worse or the job unsafe.

• Never mix cleaners. Bleach mixed with ammonia, vinegar or other products can make toxic fumes.
• Keep bleach off fabric, vinyl seats, leather and seat belts. It can fade and weaken them.
• Don't dry-brush mold or shake moldy fabric. That throws spores into the air. Wet-wipe instead.
• Don't paint or seal over mold. It keeps growing underneath.
• Don't soak walls or ceilings with water or a pressure sprayer. Extra water feeds the problem.

What should you throw out instead of cleaning?

Some things soak up water like a sponge. Once mold grows inside them, cleaning the top does not reach it. The EPA notes that soft, absorbent items with mold may need to be thrown away.

• Foam mattresses and cushions with mold or a musty smell deep inside.
• Carpet and carpet pad that stayed wet for days.
• Cardboard boxes, paper and books stored in the rig.
• Particle board shelves or cabinet bottoms that swelled or crumbled. Have these replaced, often by an RV repair shop.

When should you call a pro or an RV repair shop?

Call a detailer when the mold is only on the surface but the job feels too big. We clean and treat surface mold and mildew in RV interiors. Our technicians use steam, enzyme cleaners and odor treatment on seats, cushions, floors and hard surfaces.

We quote after we see your photos. Some old stains may not fully come out, and we will tell you that up front.

Call an RV repair shop first for soft walls, bubbled panels, a spongy floor, or stains traced to a seam. The leak and any rotted wood must be fixed. Cleaning before that just resets the clock.

Call a mold specialist when mold covers a big area, grows inside walls, or follows a flood. We are a detailing company, not a mold removal company. If your photos show more than surface mold, we will say so.

How do you keep an RV from getting moldy, in use and in storage?

Keep water out and keep air moving. While you camp, get rid of damp as fast as you make it. Run the roof vent fan when you cook or shower. Crack a vent at night, since your breath adds water to the air while you sleep.

Dry wet towels, jackets and beach gear outside. Open-flame propane heaters add water to the air too. If you use one, crack a window, follow its safety label, and keep your carbon monoxide alarm working.

Before you park the rig for the season, run through this list. Then visit every two to three weeks, and more often in fog season and after big storms. Sniff for musty air, look at the ceiling corners, and press on the floor by the door.

• Clean and fully dry the inside first. Take out food, towels and wet gear.
• Check roof seams, vents and window seals before the rains start.
• Crack the roof vents open under vent covers that keep rain out.
• Set out moisture absorber tubs (crystals that pull water from the air). Empty them before they overflow.
• If you have power, run a small dehumidifier. Empty its bucket often. Drain it into the sink only if you dump the gray tank on each visit.
• Prop open the fridge, cabinets and closet doors.
• Put a spacer mat (a mesh pad that lets air flow) under the mattress, or stand cushions on edge.
• Use a breathable RV cover, not a plastic tarp that traps water under it.
• Put a cheap humidity gauge inside. Keep it under 60 percent, and closer to 50 is better.

Frequently Asked Questions