Mold in an RV: Why Florida Humidity Causes It and How to Get It Out

By Jason Smith, Lead Detailer & RV Specialist at Polished 2 Perfection · Central Florida · ~8 min read

Mold is the RV problem we get the most panicked calls about, and it’s almost always a Florida problem before it’s a cleaning problem. A rig that would stay dry in Colorado will grow a fuzzy patch behind the dinette in a Central Florida summer, because the same humidity that makes August miserable outside is sitting inside your closed-up coach too. Below is exactly how we approach it on customer RVs around Orlando: how to tell what you’re actually looking at, how to clean it safely, when it’s past a DIY job, and, most important here, how to stop it coming back in this climate.

Is it mold or mildew? Start here

Before you clean anything, figure out which one you have, because it changes how worried you should be. Mildew is a surface fungus, usually gray, white, or yellowish, powdery, and sitting flat on a surface like a shower seal or a window gasket. It wipes off. Mold is the deeper problem: it’s fuzzy or slimy, often black, green, or blue, it penetrates into whatever it’s growing on, and it usually comes with a musty smell you notice the second you open the door. If there’s a musty smell but nothing visible, treat that as a warning, because the EPA notes mold often hides on the back of paneling, under mattresses and carpet, and inside walls around leaking or condensing pipes and windows (EPA, A Brief Guide to Mold, Moisture and Your Home).

Most of what owners panic over turns out to be surface mildew on a window seal or the rubber around a slide. Annoying, but easy. The jobs that need real work are the ones where soft materials got wet and stayed wet.

Why RVs grow mold so fast in Florida

RVs grow mold for one reason, trapped moisture, and Central Florida hands it to them two ways at once. The EPA is blunt about the mechanism: “The key to mold control is moisture control,” and mold can take hold on a damp surface in as little as 24 to 48 hours (EPA). An RV is basically a sealed box full of soft, absorbent surfaces, so once water gets in and doesn’t dry out fast, the clock starts.

The first source is leaks. On the interior mold jobs we get called to around Orlando, the culprit is far more often a slow leak (a tired roof seam, a failing window or skylight seal, a bad slide gasket) than everyday living. Water wicks in where you can’t see it and feeds mold behind the wall long before a stain shows on the surface. That’s also why our first question is always “where’s the water coming from,” and why keeping the roof and seals sound is step one; if you’re overdue there, our RV roof cleaning and sealing service exists specifically to catch those leaks before they turn into a mold bill.

The second source is the air itself, and this is the part unique to living here. The EPA says to keep indoor humidity below 60 percent, ideally 30 to 50 percent, to prevent mold. Orlando’s relative humidity, by NOAA station data, averages about 74 percent and routinely sits near 89 percent in the early morning (Current Results). In other words, a closed-up RV in Central Florida is sitting well above the mold threshold most of every day without a single drop of leaking water. One RV owner on r/GoRVing put it perfectly: “no humidifier will keep up with Florida.” They’re right, which is why prevention here has to be active, not passive.

Can you clean it yourself, or is it a pro job?

You can handle a small, surface patch yourself, but there’s a clear line, and the EPA draws it at about 10 square feet (roughly a 3-foot by 3-foot area). Under that, on hard surfaces, it’s a reasonable DIY. Over that, or if the mold is inside the walls, in soft insulation, or anywhere near the air-conditioning system, stop and bring in a professional, because disturbing it wrong spreads spores through the whole coach (EPA).

How to get mold out of an RV, step by step

The order matters more than the product. Fix the water first, or you’ll be doing this again next month.

1. Find and fix the moisture source. Track down the leak or condensation point and stop it. The EPA is explicit: if you clean the mold but don’t fix the water problem, the mold comes back.
2. Ventilate and gear up. Open the windows and roof vents, and wear gloves, goggles without vent holes, and an N-95 respirator (about $12 to $25 at any hardware store). Avoid touching mold with bare hands.
3. Dry everything out first. Run a dehumidifier and fans until the space is genuinely dry. Cleaning a wet surface just smears living mold around.
4. Scrub hard surfaces with detergent and water. For fiberglass, plastic, sealed wood, and metal, plain dish soap and water with a soft brush is what the EPA recommends. Then dry completely. You do not need a fancy chemical.
5. Pull out what’s soaked through. Porous, saturated materials (foam cushions, carpet, headliner, damp insulation) often can’t be fully cleaned, because mold grows down into the fibers. If it’s soft and it stayed wet, plan to replace it.
6. Dry again and re-check in a few days. The job isn’t done until the surface is dry, the musty smell is gone, and nothing has come back on a return look.

One caution owners miss: dead mold still triggers reactions, so killing it isn’t enough. It has to be physically removed, not just sprayed and left (EPA).

What actually kills RV mold — vinegar, peroxide, or bleach?

For most small RV jobs, plain detergent and water is the EPA-recommended default, and white vinegar is the DIY favorite that experienced owners reach for first. Bleach is the one to be careful with. Here’s how the common options actually stack up on an RV.

Two rules that come straight from the EPA and save people real grief: don’t reach for bleach as your automatic first move, because it’s not recommended as a routine mold cleaner, and it should never be mixed with any ammonia-based product, since the combination produces toxic fumes. And don’t paint or caulk over a moldy spot to hide it; paint won’t stick and the mold keeps growing underneath.

How to keep mold from coming back in a Florida RV

Removal is the easy part; in this climate, prevention is the whole game. Because Central Florida air sits above the EPA’s 60 percent mold threshold most of the day, you can’t just air the rig out and hope. You have to actively pull moisture down and keep water from getting in. This is the routine we give Central Florida RV owners:

• Run a dehumidifier or the A/C on a schedule, even in storage, even when you’re not in it. A small compressor dehumidifier or DampRid in the cabinets and closets is cheap insurance against 89 percent morning humidity.
• Keep the roof and every seal sound. A roof seam or window seal that leaks is the number-one interior-mold source we find. Inspect the roof and reseal on schedule; this is the highest-leverage thing you can do.
• Ventilate when you’re in it. Run the vent fan when you cook or shower, and crack a roof vent to move moist air out instead of letting it settle into the cushions.
• Don’t let fabrics touch cold exterior walls. Mattresses and cushions pressed against a wall trap condensation behind them, so leave an air gap.
• Dry any spill or leak within 24 to 48 hours. That’s the EPA window; beat it and mold usually never starts.
• Deep-clean the interior seasonally, especially after the June-to-September rainy season, when we see mold calls spike. A thorough interior detail catches early mildew on seals and vents before it becomes mold.

If you’d rather not chase it yourself, that seasonal reset is exactly what a full mobile RV detail is for. We come to your driveway or storage lot anywhere in Central Florida, clean and protect the interior and exterior, and flag any seal or roof issue before it turns into a moisture problem. If the outside is already chalky or streaked from sitting in the sun, our RV exterior detailing and restoration handles that in the same visit.

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