RV Freshwater Drain Valves: Hose Barb, Threaded & Low-Point Parts Guide

A freshwater draincock lets you empty a low-point section of an RV's fresh-water plumbing or a tank drain without disconnecting a line. Many look similar from the outside, but the connection behind the valve can be a hose barb or male pipe thread. Choosing the wrong style can prevent the replacement from sealing or fitting the existing plumbing.

Freshwater drain valve connection diagram

These simplified layouts show the two common arrangements. They illustrate the relationship between plumbing parts, not a complete RV manufacturer's plumbing schematic.

RV freshwater drain valves with hose-barb connections

These valves are for compatible flexible drain hoses. JR Products offers a dual-size 3/8- to 1/2-inch barbed connection in white or black; LaSalle Bristol and Petersen also offer individual 3/8- and 1/2-inch models.

White dual-size hose-barb drainJR Products 03182For compatible flexible freshwater drain hoses; compare the hose inside diameter and original mounting.View this valveBlack dual-size hose-barb drainJR Products 04-62415The black JR Products dual-barbed version for compatible freshwater plumbing; store listing also identifies it as 0462415.View this valveWhite 3/8-inch barbed draincockLaSalle Bristol 73301White plastic draincock with a mounting flange; select it for a compatible 3/8-inch hose connection.View this valveWhite 1/2-inch barbed draincockLaSalle Bristol 73302Flanged white drain valve for a compatible 1/2-inch flexible freshwater hose, not a threaded female port.View this valveColonial-white 3/8-inch hose-barb drainPetersen Molding 18959CWSingle-size 3/8-inch barbed polypropylene drain valve; match the original hose and exterior appearance.View this valveColonial-white 1/2-inch hose-barb drainPetersen Molding 18958CWSingle-size 1/2-inch barbed polypropylene valve; not an NPT threaded model.View this valve

RV freshwater valves with male pipe threads

Choose the threaded group when your existing drain fitting screws into a female port. JR Products 03175 has a dual-size male-thread design, while the LaSalle Bristol and Petersen options below identify a single nominal thread size.

White dual-size male-thread drainJR Products 03175A threaded replacement for compatible female drain ports; this is not the hose-barb version 03182.View this valveWhite 3/8-inch male-thread draincockLaSalle Bristol 73304Single-size male pipe-thread valve without a mounting flange. Check the female port before replacing.View this valveColonial-white 3/8-inch male-thread drainPetersen Molding 18957CWSingle-size threaded polypropylene valve. Confirm the port's thread form and finish before ordering.View this valveColonial-white 1/2-inch male-thread drainPetersen Molding 18966CWSingle-size 1/2-inch male-thread polypropylene replacement; not for a plain hose-barb connection.View this valve

Freshwater drain-valve part-number comparison

For an exterior-mounted replacement, also compare the original valve's mounting flange and body clearance. Similar barbed or threaded sizes do not confirm a direct physical replacement for a particular RV model.

Before replacing a freshwater draincock

1. Locate and identify the drain. Confirm it belongs to the freshwater tank or plumbing low point, not the separate black- or gray-water holding-tank gate valve.
2. Relieve water pressure. Turn the freshwater pump off, disconnect pressurized city water and open a faucet before working on the valve. Drain the affected section into a suitable container.
3. Check the hidden connection. Inspect for a hose barb or male-thread connection. Measure the hose inside diameter or identify the port's exact thread size and type.
4. Compare mounting details. Check flange position, wall thickness, clearance for the operating lever and the hose's or pipe's routing. Only reuse sound, appropriate mounting components.
5. Test after reassembly. Refill and repressurize the system according to the RV manufacturer's instructions. Inspect the inlet joint and valve for leaks, then check that the drain opens and closes correctly.

If you are winterizing the freshwater system, see the RV freshwater winterizing pump converter and hand-pump guide for other service tools. These drain valves are separate components, not winterizing pump kits.