Enjoying time with family and friends in your RV should be worry-free, especially when it comes to your holding tanks. Odors and clogs can ruin a trip, but regular deep cleaning of your black tank helps prevent these issues. Over time, sludge buildup can cause persistent smells, slow dumping, and a black tank that fills too quickly. Treat your holding tanks with a clean slate by deep cleaning your black tank every 4 To 6 months.