Twelve by twelve, 32 inches long: the 27W is a beam of a tank. Its square section is the detail that matters - a 12 inch cube profile drops into cockpit lockers, settee bases, and the square voids that boat and van interiors generate everywhere, while the length brings the total to 17 gallons. Square sections also brace well: flat faces land against flat bulkheads with full contact.
It comes from the Water / Waste Holding Tank series, Ronco's one-shell-two-jobs line. Ordered with fresh fittings it is a potable tank, molded in FDA-compliant polyethylene. Ordered with waste fittings the same body becomes a gray or black holding tank. You choose at order time; the molding is identical.
Wall thickness shows in the numbers - 17 lb empty, sturdier than its capacity suggests - and a full load is about 142 lb of water at 8.34 lb per gallon. Its longer and flatter relatives fill out the RV water tanks category; dedicated waste geometry lives under RV holding tanks; the same square-section logic serves boat installs.
Molded in Tustin, California, where Ronco has done nothing but tanks since 1974. Fittings go in per order - spin-weld or threaded, at the marks you provide: print the drawing below or lay it out on the click-to-place planner. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics 27W 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.
