Six inches. That is the entire height of the Ronco Plastics B406, a 60 x 21 x 6 inch molding that still finds 26 gallons by running five feet long. It is the tank for spaces everyone else writes off: under floors, beneath berths, in the shallow pan above a chassis rail. The B-series dual-role shell serves as potable fresh water storage in food-grade polyethylene or as an ultra-low-profile gray or black holding tank, per the fittings ordered.
The molding is heavily built at 92 lb, stiffness a six-inch-tall shell needs across a five-foot span. Full, it adds about 217 lb of water at 8.34 lb per gallon.
In a tank this shallow, fitting placement is everything; a low-point drain in the wrong spot strands water forever. Print the drawing below, mark your points carefully, and the factory installs fittings per order, spin-welded or threaded to those marks. The fitting planner on this page walks you through it. Ronco has built to order in Tustin, California since 1974.
More low-profile options under boat tanks and RV holding tanks. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B406 dimensional drawing - print it to plan your install and mark exactly where you want fittings located; Ronco installs spin-weld or threaded fittings to your marked spec.
