It may surprise you, but mould can grow even in the absence of water leaks in the RV. Condensation, frequently overlooked as a contributor to mould, should be a suspect too. Leaks and condensation should both be addressed to avoid mould.
Mould needs four things to grow.
- Spores - These are everywhere.
- Food - Mould prefers organic things like bread, wood, etc.
- Temperature - Mould prefers temperatures that we humans find comfortable too.
- Moisture - Mould thrives well in a humid environment.
You can control #4 only!
Preventing leaks and high humidity will address mould issues, to a great extent. Ventilate your RV as much as, and as frequently as possible because that will drive out excessive moisture in the RV. Keep relative humidity levels below 50% and you may never see mould in the RV.