Valterra R8030 & R8036 ABS Fresh-Water Tanks: Sizes & Fittings

Valterra's black ABS fresh-water tanks are useful when a replacement needs to fit a long, narrow storage compartment and operate as a low-pressure water reservoir. R8030 and R8036 have the same two shorter dimensions; the 18-gallon tank is six inches longer than the 15-gallon tank. Before selecting either, measure the installation space and check how the water will be filled, drained and delivered.

R8030 vs R8036: capacity and dimensions

Both tanks use black ABS plastic, one-piece extruded construction and internal baffles spaced every 18 inches. The dimensions describe the tank body as published by Valterra; leave additional room for the fill elbow, hoses, retaining supports and safe servicing access. They are not vehicle-specific fit guarantees.

Understanding the factory connections

Both tanks have six 3/8-inch threaded fitting inserts—three on each end. Those inserts provide locations for connections, but they are not a complete gravity-fill hose assembly. Check which original fittings are used for the fill, outlet and vent and how the tank is supported. Use fitting materials and joining methods specifically approved for the ABS tank.

Valterra RK907 is a separate ABS tank fill kit. It includes a 1¼-inch 90-degree barbed fill elbow, two 3/8-inch female drain/vent adapters, two 3/8-inch 90-degree barbed adapters, a 3/8-inch male pipe plug and ABS solvent cement. It does not include a tank, hose lengths or vehicle mounting supports. Compare your installation before selecting the elbow orientation.

What to check before installing a tank

1. Measure the available space. Compare the 30-inch and 36-inch lengths, and check the 16 × 8-inch cross section. Allow clearance for plumbing connections, bracing and any nearby chassis members.
2. Verify the system's pressure design. These tanks are for low-pressure gravity fill/drain and not electric-pump use. For an electrically pumped RV water system, choose a tank specifically approved for that application.
3. Confirm the gravity-fill route. Check the inlet-hose angle, vent routing and a safe way to prevent overfilling. The 90-degree RK907 elbow may suit some tight layouts, but the fit depends on your actual hose path.
4. Plan the mounting and support. Water weighs substantially more than the empty tank. Support the installed tank in accordance with the vehicle and tank manufacturer's requirements; do not depend on the fittings to carry its weight.
5. Check joining and sanitation procedures. Use approved ABS fittings and cement according to their instructions. Rinse and sanitize the completed drinking-water system before use, then inspect for leaks.

Shop exact Valterra tanks and fittings

These cards link to the corresponding NewRVParts listings. Order availability is shown on each product page; items ship from supplier warehouses, without warehouse viewing or pickup.

Valterra R8030

15-gallon ABS fresh-water tank

15 US gal (57 L); 30 × 16 × 8 in outside dimensions

View exact product and availability

Valterra R8036

18-gallon ABS fresh-water tank

18 US gal (68 L); 36 × 16 × 8 in outside dimensions

View exact product and availability

Valterra RK907

ABS fresh-water tank 90-degree fill kit

90-degree fill elbow, tank adapters and solvent cement

View exact product and availability

Related RV freshwater parts

For gravity-fill hatches and exterior hose connections, compare our Valterra city-water versus gravity-fill hatch guide. For drain fittings and low-point valves, see the freshwater drain valve reference. These are separate components; match thread, hose and system requirements before combining them.