What Size RV Sewer Hose Do I Need?

Buy 20 feet, supplied as two 10-foot sections. The diameter is standardized at three inches, so that is not a choice you have to make. Ten feet reaches at the majority of sites; the second section covers the ones where the inlet is at the wrong end of the pad, and those are common enough to matter.

Part of our sewer and water guide. Once you have settled the length, the kit choice is in the sewer hose roundup.

The short version

Diameter: not a decision

RV sewer hose is three inches in diameter, and the bayonet fitting at the rig end is a common standard across brands. That means hoses, couplers, elbows and adapters generally interchange regardless of who made them.

The practical consequence is good news: you cannot buy the wrong diameter, a mid-trip replacement section does not have to match your existing brand, and a spare fitting is never wasted. Brand differences are covered in Camco versus Valterra.

Why two 10-foot sections beats one 20-foot hose

A single 20-foot hose means that at every site where you only need 10, you are laying ten feet of slack hose on the ground. Slack means dips, dips hold liquid, and liquid sitting in a hose is exactly what you are trying to avoid.

Two sections let you run the length the site actually needs. It also means a damaged section is half a replacement rather than a whole one, and that you can lend a section to the neighbor who came up short.

Longer is not better

Thirty or forty feet sounds like insurance. In practice it is more bulk to store, more to rinse, more to carry, and more length over which to lose your slope. Over a long run the fall from your outlet to the park's inlet has to be spread thinner, and slope is what makes the tank drain properly.

Twenty feet, in two sections, plus a support, handles almost everything. Anything beyond that is solving a problem you will meet a handful of times in a decade.

What to buy

A 20-foot kit in two sections, a support the same length, and a clear elbow so you can see when the tank has finished.

Best for The first sewer hose to own

Camco RhinoFLEX 20-Ft Sewer Hose Kit

The complete first kit: 20 ft in two sections, both fittings, and a clear elbow so you can see when the tank is actually done.

Check price on Amazon#ad we may earn a commission

Best for The support most people should buy

Camco Sidewinder RV Sewer Hose Support (20 ft)

The item first-timers most often arrive without: a fixed-slope cradle that makes the tank actually drain instead of sit.

Check price on Amazon#ad we may earn a commission

Best for Seeing when the tank is done

Camco RhinoFLEX Clear 45-Degree Sewer Adapter

The clear elbow: the cheapest way to know a black tank is genuinely empty rather than probably empty.

Check price on Amazon#ad we may earn a commission

What to do when it will not reach

It happens. Options, in order of preference:

Reposition the trailer. Free, and usually possible. Moving four feet forward is much easier than anything else on this list.

Add your second section. Which is why it is in the compartment.

Ask the park. Many parks have a spare section behind the office for exactly this, because it happens to somebody every week.

Use the dump station instead. Perfectly reasonable for a short stay. Connect nothing, dump on the way out.

What not to do is stretch a hose taut between the rig and the inlet. A hose under tension pulls on both fittings, and the fitting is where these fail.

Sizes of the other things people ask about

The sewer inlet at the park is typically a four-inch opening, which is why the clear elbow has a stepped or threaded adapter on it. That is also why a rubber donut seal fits the inlet rather than the hose.

Your rig's outlet is a three-inch bayonet. Universal in practice across travel trailers.

The tank rinse inlet, if your trailer has one, is a garden hose thread. Use a dedicated rinse hose for it, never your drinking-water hose — see the black tank flush guide.