Ronco Plastics 3H - 35 Gallon Plastic RV Holding Tank (64.0" x 32.0" x 8.0")

Lay a sheet of plywood flat and you have roughly the idea: the 3H spreads 35 gallons across a 64 x 32 inch footprint at just 8 inches tall, the widest, flattest holding tank in this stretch of Ronco's line. It is the shape of a coach floor with a shallow void and no other options, and it holds serious volume there precisely because it refuses to be tall. The blank weighs about 45 pounds, befitting all that surface area.

Duty is gray or black water, never potable, and the full-load engineering deserves attention: 35 gallons at 8.34 pounds per gallon is roughly 292 pounds spread over fourteen square feet of bottom, which is friendly pressure per square inch but demands flat, continuous support; a pancake tank sagging between two straps will oil-can and fail early.

Ronco Plastics rotomolds the 3H in Tustin, California, where it has built RV and marine tanks since 1974, and installs your fittings, spin-welded or threaded, at the positions you mark. On a tank this flat the outlet must sit at your installation's true low point, so print the drawing below, mark it against the coach rather than the bench, and order to that sheet. Alternatives in the neighborhood include the 4H side-dump at 53.75 x 25 x 8 inches, the 20H at 63 x 20.25 x 8.5, and the deeper 48H at 35 x 25 x 12.75; the full family is at RV holding tanks. OneSource Plastics is an authorized Ronco Plastics dealer.

Technical drawing: download the Ronco Plastics 3H 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.