Slim is the B251's whole argument: 27.5 x 14.75 x 9.5 inches, a 15 gallon tank barely wider than a toolbox. It slips behind console panels, alongside stringers, under bench seats - the leftover spaces where a boat or camper hides its plumbing - and turns one of them into a real water supply.
The B-series dual-role design means those 15 gallons serve either side of the system. Fresh-fitted, the food-grade polyethylene molding carries potable water; waste-fitted, it is a compact gray or black holding tank for builds where a full-size waste tank will not fit. It ships blank: print the drawing below, mark your fitting locations, and use the on-page fitting planner to spec the spin-weld or threaded fittings Ronco installs to your marks.
Nineteen pounds empty, about 125 lb full - light enough to install alone, heavy enough loaded to deserve a proper strap. Tustin, California molded, as all Ronco tanks have been since 1974. Find the next size in either direction in our boat tank category or across the line at the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B251 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.
