Water damage is widely considered the number one enemy of an RV. Because RVs flex and bounce down the highway, their seals are under constant stress, making leaks incredibly common.
Catching a leak early can mean the difference between a quick bead of lap sealant and a massive, expensive structural repair. Here is exactly what to look (and feel) for.
Visual Signs (What You Can See)
The most obvious signs of a leak happen right on the surfaces of your RV, though they sometimes look like minor cosmetic issues.
Delamination: If you have a fiberglass RV, look down the sides of the exterior from an angle. If you see bubbling, rippling, or areas where the fiberglass looks separated from the backing, water has gotten inside the wall and dissolved the adhesive.
Water Stains and Discoloration: Look at the ceiling, especially around vents, skylights, and the air conditioning unit. Water stains usually appear as light brown rings or yellowish discoloration.
Peeling or Wrinkling Wall Coverings: RV walls are usually covered in a vinyl-coated wallpaper. If water gets behind it, the wallpaper will wrinkle, bubble, or peel away from the seams.
Rusted Fasteners: Look at the screws on the exterior trim, around windows, and inside the cargo bays. If the screw heads are heavily rusted, moisture is actively sitting in those areas.
Tactile Signs (What You Can Feel)
Sometimes you will feel a leak before you see it. When water soaks into the luan (thin plywood) and foam core of an RV, it destroys its structural integrity.
Spongy Floors: Walk heavily across every inch of the floor, paying special attention to the areas around the toilet, shower, refrigerator, and the edges of slide-outs. If the floor feels soft, dips, or gives under your weight, the subfloor is rotting.
Soft Spots on Walls or Roof: Press firmly on the interior walls below windows and in the corners of the RV. If the wall flexes or crunches, there is rot behind it. If you have a walkable roof, step carefully—if you feel a dip or a "spongy" spot, water has compromised the roof decking.
Swollen Cabinetry: Most RV cabinets are made of particleboard or MDF covered in a veneer. When MDF gets wet, it swells up like a sponge. Run your hands along the bottom edges of the cabinets, especially near the sink and floor.
Odors (What You Can Smell)
Close up the RV for a day or two on a warm day, then step inside.
The Musty Smell: If the RV smells like an old basement, mildew, or damp earth, you almost certainly have trapped moisture. Many sellers will try to mask this with air fresheners, so be highly suspicious of an RV that smells overwhelmingly like bleach or plug-in fragrances.
Where to Check First
If you suspect a leak, these are the most notorious failure points:
The Roof Seals: The front and rear caps where the roof meets the walls, and around any roof penetrations (plumbing vents, TV antenna, A/C).
Slide-Outs: Check the rubber sweep seals around the outside and the floor corners inside.
Clearance Lights: The small marker lights on the top front and rear of the RV are a very common, easily missed entry point for rainwater.