The Ronco Plastics B158 puts 36 gallons into 30.5 x 21.5 x 13.75 inches - a squarish, low package that fits under dinette seats and berth flats where longer tanks will not turn the corner. It is a marine water / waste series molding, which means the duty is decided at order time: potable fittings make it a fresh water tank in FDA-compliant polyethylene; waste fittings make it a 36 gallon gray or black holding tank. Same shell, two careers.
Ronco has run this made-to-order model from Tustin, California since 1974: fittings installed per order, spin-welded or threaded, positioned to your marks. The drawing below is dimensioned for exactly this - print it, lay out the fill, vent, and outlet against your compartment and hose runs, then commit the plan through the fitting planner on this page.
It ships at 33 lb and holds about 300 lb of water when full, so the golden rule applies: support the bottom completely, strap it like the road or sea will test it, and keep the mass low. Cross-shop footprints at boat tanks and RV water tanks, see the full range at the Ronco Plastics hub, and get shipping to your ZIP from the freight estimator. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B158 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.
