The Ronco Plastics B407 is a 135 gallon underfloor slab, 75.5 x 33.25 x 14 inches, molded for coaches and large rigs that carry serious water. Over six feet long and under fifteen inches tall, it converts an entire basement bay into fresh water capacity. Like all B-series moldings it is dual-role; potable fittings make it a food-grade fresh water tank, waste fittings make it a very large holding tank.
The load is substantial: about 1126 lb of water at 8.34 lb per gallon, plus the 147 lb molding. Distribute it across chassis structure along the tank's full length, never across an unsupported span.
Fittings are installed per order, spin-welded or threaded to your marks; on a tank this long, that is the difference between full drainage and permanent standing water. Print the drawing below, plot every connection and low point, and use the fitting planner on this page to submit the layout. Ronco has custom-finished tanks in Tustin, California since 1974.
See other large RV water tanks and RV holding tanks, and price the haul with the freight estimator. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B407 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.
