Find the leaks by hosing the camping trailer in sections. Because water travels, the wet spot you see inside the trailer may not be near the source of the leak. Use a hose set at a low flow on different sections on the outside of the trailer to see where the water is entering the trailer.
Allow the trailer to dry out once you have found the leak. Open doors and windows to ventilate the interior.
Clean the outside of the trailer around the leak with some dishwashing soap and water (1/2 teaspoon soap to 1 gallon of water) and a rag. Dry the area with a towel after cleaning.
Use a rubber roof sealant to seal small cracks or spaces around the sunroof. These can typically be used on areas made of rubber, fiberglass, wood, aluminum or steel. Use the product according to the label's instructions.
Use an RV patch kit or sealing tape for large cracks on the roof, walls or for the canvas of a pop-up camper. These products are sold at most RV or camping trailer supply stores and include instructions specific to the product and type of leak you need to seal.With use and age, most camping trailers, whether hard-sided or a pop-up, eventually will leak. These water leaks can be difficult to find. But if you take the time to find and repair the leak immediately, you can prevent mold growth and damage to the trailer that will be more extensive and costly to fix.