Ronco Plastics

Sizing a replacement holding tank is a one-way ratchet: you can plumb a bigger tank into a smaller role, but never the reverse, and the 38H's 32 gallons make it the step-up candidate when your old 30...

Same 30 gallons, different arithmetic: the 39H spreads its volume across 46 x 22 inches at only 9 inches tall, while its sibling the 22H stacks it deeper at 39 x 25 x 12. Pick by the dimension your...

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...

Fourteen gallons is where a holding tank stops being a day tank and starts covering a real trip: enough gray water margin for several days of dishes and quick showers for two. The 40H hits that mark...

The 41H is built around its outlet: a 12-gallon holding tank with a side dump, meaning the waste valve exits the sidewall rather than the bottom. On rigs where there is no clearance below the tank...

The 42H is a wall of a tank: 91.5 inches long, 16 inches tall, and only 7 inches thick. Fifteen gallons of holding capacity stood on edge like a panel. Builders spec this shape to run vertically...

The 43H runs 81 inches along a frame rail while standing just 7.75 inches tall and 11 inches wide - 20 gallons of holding capacity shaped like a structural member. Rail tanks like this are how...

Nearly seven feet of tank. The 44H runs 80.75 x 14 x 6.75 inches - a 12-gallon holding tank stretched into a beam that lays along a frame rail or under a full-length slide floor where nothing...

Six feet two inches of tank, eight and a quarter inches tall. The 45H spreads its 25 gallons across a 74 x 15 x 8.25 inch envelope, which is the geometry of an underbelly installation: slung low...

The 46H spends its 13 gallons on area instead of depth: a 52 x 30 inch slab standing only 8 inches tall. That two-and-a-half-foot width is unusual in the holding line and it exists for wide, shallow...

The 47H anchors the large end of Ronco's mainstream holding tank boxes: 43 x 22 x 11.25 inches, 27 gallons, the sort of tank that serves as the black tank under a full-time couple's fifth wheel. The...

Measure your bay first: if you have 35 inches of length, 25 of width, and 12.75 of height, the 48H puts 36 gallons of waste capacity in it. This is the fully-dimensioned member of Ronco's 36-gallon...