Last Updated on September 22, 2026 by Umar Farooq
The machine is rarely the limiting factor. Four things are: the weight you are adding to the rig’s cargo allowance, whether your water pump can hold the washer’s minimum inlet pressure, how much grey tank you have per cycle, and whether the floor is level and stiff enough for a spin. Check those before you shop — a unit that fits the cupboard can still be the wrong answer.
Most guides on this compare models. This one covers the constraints those models have to live inside, because that is where the disappointment happens.
The weight is a safety number, not a preference
Everything you add to an RV comes out of the cargo carrying capacity on the placard, and a washer-dryer is not a light addition once you include the plumbing, the mounting and the water it holds during a cycle.
Deduct the whole installed weight from your CCC, not just the appliance. That is a loading limit rather than a suggestion, and it is the one item on this page that has nothing to do with laundry performance. If you are close to your limit already, this decision is made for you.
Water is the part people forget. A wash cycle holds several gallons in the drum and the same again in the tank feeding it, and water weighs roughly 8.3 pounds a gallon. That load moves around while you drive.
Your pump has to hold the washer’s minimum pressure
Here is the appliance constraint nobody mentions, and it is checkable before you buy anything.
Washing machines publish an inlet pressure range. LG’s is explicit: “Water supply pressure must be between 14.5 PSI and 116 PSI” (inlet hose installation). Samsung gives essentially the same band in metric, 0.5 to 8 bar.
A typical RV pump can meet that number on paper. What it cannot always do is hold it while something else is running — open a tap or flush while the washer is filling and the pressure drops. That matters because the machine does not fail loudly when it is underfed; it just takes longer. Whirlpool names household water pressure directly among the things a long cycle is built out of: the estimated time remaining “is based on: size and type of load, cycle selection, option selection, household water temperature and pressure, and unbalanced load detection” (long cycles on a front load washer). And on a fill sensor that never sees the level it expects, you will eventually get a fill error instead.
There is a temperature constraint on the same LG page worth knowing: “The water supply for the hot water valve should be at least 120°F.” An RV water heater is small, and a warm wash can empty it before the machine has finished filling.
The grey tank is usually what actually stops you
Off hookups, this is the real limit. A wash cycle’s water — wash plus rinses — goes into the same grey tank as your showers and your sink, and it does not care that you are three days from a dump station.
The practical arithmetic is simple and worth doing before you buy: take your grey tank capacity, subtract what your household already puts in it per day, and see how many cycles fit. For a lot of rigs the honest answer is one small load every few days, which is a very different proposition from the laundry room at home.
On hookups this constraint disappears entirely, which is why people’s experience of RV laundry varies so wildly. It is not the machine. It is where you park.
RV washer dryer formats: vented, ventless and combo
Three formats, and the difference is about moisture and space rather than washing.
- Stacked washer and separate vented dryer. Dries fastest and best, and needs a 4-inch vent through an exterior wall. That hole is the part people hesitate over, and it is also the part that makes the dryer work properly.
- Ventless combo, one drum. No hole in the wall, and no transferring wet laundry. It dries by condensing moisture and sending it down the drain, which is slower — often several hours — and it dries a smaller load than it washes.
- Portable machines. No installation at all; fill from a tap, drain into the shower or a bucket. The cheapest way to find out whether you will actually do laundry on the road before committing floor space to it.
A ventless combo is the most common choice and the one that disappoints most often, for a mechanical reason: condensing dryers need a small load to work in a reasonable time, so the practical capacity is the dry rating, not the wash rating.
Levelling and spin, which an RV makes harder
A washing machine balances a spin by being level and by standing on something that does not move. An RV is frequently neither.
Level the rig first, then level the machine to it — the machine cannot compensate for a site that slopes, and an out-of-level drum will abort spins and leave laundry soaked. The method is the same as at home: how to level a washing machine.
Floor flex is the second half. A compact machine at 1,000+ rpm on a flexing plywood floor transmits everything into the structure. Keep loads small and spin speeds moderate; a machine that walks in a fixed house will do considerably more in a moving one (washing machine walks during spin).
FAQ
Is an RV washer dryer worth it?
On full hookups, often yes. Off grid it is limited by your grey tank more than anything else, and many owners find one small load every few days is the realistic ceiling.
What size washer fits in an RV?
Compact units, typically around 2 cubic feet. Measure the space, the doorway it has to come through, and check the installed weight against your cargo capacity.
Can you use a regular washing machine in an RV?
Physically sometimes, practically rarely. Weight, water pressure and grey tank capacity all push toward a compact machine designed for the job.
Why does my RV washer take so long to fill?
Usually water pressure. The machine needs a minimum inlet pressure and an RV pump can drop below it when another tap is open — Samsung lists low pressure as a documented cause of long cycles.
Do RV washer dryer combos actually dry?
They dry, slowly, and a smaller load than they wash. Budget several hours and load for the drying capacity rather than the washing capacity.
Does adding a washer affect my RV’s weight rating?
Yes. The unit, the plumbing and the water it holds all come out of your cargo carrying capacity, and that is a loading limit rather than a guideline.
Do the tank maths before you shop
Work out your grey tank maths and your cargo capacity before you look at a single model, because those two numbers decide this and no appliance feature changes them. If both clear, a compact unit is genuinely useful — and if they do not, a portable machine and a laundromat stop will cost less and annoy you less.
