Valterra HydroFlush 45° vs 90°, Flush King & Tank Rinse Parts

There are two ways to rinse an RV holding tank without putting a wand through the toilet: connect a removable reverse-flush fitting at the sewer outlet, or install a permanent spray system in the tank. Valterra's HydroFlush, Flush King and fixed tank rinse products are different designs. This guide explains where each one connects, what it does, and how to choose the correct parts for your RV.

Compare HydroFlush, Flush King and related parts

Where the components fit in the system

For a temporary reverse flush, a HydroFlush or Flush King fitting sits at the outlet between the RV and sewer hose. The separate gray flushing hose supplies rinse water to the fitting's water port. The 45° and 90° HydroFlush models and the Flush King are alternative choices—not three parts that need to be installed in a row.

Rinse-water connection: A separate flushing hose connects the water source to the rinsing fitting, using the required backflow protection and shutoff controls.

Valterra tank-rinsing parts and photos

F02-4100 — RV HydroFlush 45°

The clear 45-degree adapter adds a rinse-water connection to the waste outlet. It is used to help flush tanks, pipes, valves and the connected sewer hose. Valterra specifies an internal backflow preventer and removable anti-siphon valve.

View F02-4100

F02-4110 — RV HydroFlush 90°

The 90-degree HydroFlush serves the same general rinsing purpose as the 45-degree model, but turns the discharge through a right angle. Its clear body helps show the water leaving the drain line. It also includes the backflow-prevention and anti-siphon components identified by Valterra.

View F02-4110

F02-4350 — Flush King reverse-flush valve

Flush King adds a manually operated gate valve to the rinse fitting so the tank can be filled and drained as instructed. Valterra includes a quick water shutoff and an anti-siphon valve. The clear section helps you observe the discharge.

View F02-4350

W01-4300 — 25-foot gray flushing hose

This gray non-drinking-water hose measures 25 feet long with a ½-inch inside diameter. Use it for the sanitation rinse-water connection; do not reuse it for the RV's potable-water hookup.

View W01-4300

F02-4170 — HydroFlush permanent tank rinse system

This is a different design from the removable sewer-outlet adapters. The kit includes a multi-directional tank sprayer, exterior wall inlet, fixed hose and mounting hardware for permanent installation on a compatible black- or gray-water tank.

View F02-4170

45° versus 90° HydroFlush: which angle?

The F02-4100 and F02-4110 both provide a rinse-water connection, clear viewing section and the backflow-prevention components specified by Valterra. The main difference is the angle of the discharge. Choose the 45° or 90° version based on the position of the RV waste outlet, the direction the sewer hose needs to travel and the room available to install the fitting without twisting or stressing the hose.

When to choose Flush King

The F02-4350 Flush King has its own large gate valve in the discharge path. This gives you a way to temporarily hold rinse water and drain it through the connected sewer hose according to Valterra's instructions. It can help clear clogs in the waste line and rinse tanks with difficult plumbing bends. It is a removable service accessory, not a replacement for an RV's normal holding-tank dump valves and not a permanent installation.

Manufacturer instructions and parts identification

Check before ordering or rinsing

1. Identify whether you need a temporary sewer-outlet attachment or a permanently installed tank sprayer.
2. For a removable fitting, check the waste-outlet bayonet connection, sewer-hose coupling and space beneath the RV.
3. Choose the connection angle or valved Flush King design that meets your service needs, rather than selecting by appearance alone.
4. Use separate sanitation-rinsing equipment and the appropriate anti-siphon/backflow devices. A gray flushing hose must not be reused as a drinking-water hose.
5. For a fixed F02-4170 installation, confirm the tank wall, accessible mounting position and exterior hose routing before any drilling or sealing.
6. Follow the manufacturer's valve sequence while rinsing, observe the tank level and discharge, and clean and store the equipment after use.

Other sanitation reference guides

For bayonet fittings, hose adapters and dump-station elbows, see our Valterra sewer-connection guide. For other ways to clean deposits inside the tank, compare spinning and flexible tank-rinsing wands. Our waste-valve replacement guide covers the separate gate valves and pipe ends.