Ronco Plastics 4H - 35 Gallon Plastic RV Holding Tank with Side Dump (53.75" x 25.0" x 8.0")

The 4H solves a specific plumbing problem: a 35-gallon waste tank that dumps out the side instead of the end. On coaches where the termination valve sits outboard of the frame rail, a side-dump molding means the drain run goes straight out - no elbows trapping waste under the floor. The pan itself is 53.75 inches long, 25 inches wide, and only 8 inches tall, built to slide into a genuinely shallow underfloor cavity.

That 8-inch height is the defining spec. Most 35-gallon tanks buy their capacity with depth; the 4H buys it with length and width, so it fits where taller tanks simply cannot. Its side-dump counterpart one size up is the 61H, 42 gallons at 45 x 24.5 x 12 inches, and there is a smaller one in the 34-gallon 20H at 63 x 20.25 x 8.5 inches. If end dump works for your layout, the standard 35-gallon 3H is the wide-pan alternative.

One-piece rotomolded polyethylene, 32 lb as a blank shell, roughly 292 lb full - gray or black water only. Ronco installs fittings per order at its Tustin, California plant, spin-welding or threading them wherever you mark: print the drawing below, note your drain, vent, and inlet positions, and the tank comes plumbed to your coach, the way Ronco has done it since 1974. More shapes at RV holding tanks.

OneSource Plastics is an authorized Ronco Plastics dealer.

Technical drawing: download the Ronco Plastics 4H 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.