How to choose an RV or marine tank
- Sort by what it holds. Fresh water and waste are shopped separately. Fresh water tanks are in RV water tanks, and black and grey water tanks are in RV holding tanks.
- Then pick road or water. Boat tanks have their own groups: marine water tanks and marine holding tanks.
- Compare models, not only gallons. Many capacities come as several models. Custom Roto-Molding lists 20 gallon RV water tanks as W-81 and W-51, and 40 gallon tanks as W-1, W-205 and W-248, so check each model's length, width and height against your space.
- Search the code when replacing. Custom Roto-Molding model codes start with W for RV water tanks, H for RV holding tanks and MW for marine water tanks. If you know the code of the tank you are replacing, search it before you compare sizes.
RV and marine tank questions
Will an RV tank fit a camper, trailer or van? It will if the tank fits the space. Fit comes from the tank's length, width and height and where its openings sit, not from the type of vehicle, so the same tank can serve a camper, a travel trailer, a motorhome or a van build.
What sizes do RV and marine tanks come in? Capacities run from 2 to 375 gallons. Examples include 4, 20 and 55 gallon RV fresh water tanks, 6, 10, 25 and 40 gallon marine holding tanks, 5, 16, 32 and 50 gallon marine fresh water tanks, and a 120 gallon RV holding tank from Custom Roto-Molding.
Can a marine tank go in an RV? Tanks sold as Marine & RV Tank models are named for both uses, in sizes such as 4, 14, 36, 80 and 100 gallons. Other marine tanks are grouped for boats, so check that a tank's size and openings suit your RV before you choose it.
What else do I need to install a new tank? Usually fittings. The DIY Fitting Kit for RV & Marine Tanks is sold in RV & marine tank accessories. Match each fitting to the opening on the tank you choose and to the line it connects to.
