How to Winterize an RV Dishwasher and Washer-Dryer: A Step-by-Step Guide

Protect the appliance pumps, water lines, and drains with a model-specific winterization plan before freezing weather arrives.

An RV with a dishwasher, washing machine, or washer-dryer combo needs a little more attention than a basic water system. Small amounts of water can remain in inlet valves, pumps, hoses, filters, and drain traps. Because appliance designs vary widely, the manufacturer’s instructions for your exact model take priority over any general guide. If a manual does not explain how to winterize the appliance, contact the manufacturer or an RV service professional before adding antifreeze or using compressed air.

Before you begin

• Find the owner’s manuals for the RV and each appliance. Record the make and model numbers.
• Have towels, a shallow pan, gloves, and the RV-approved winterizing equipment specified by your manuals.
• Use only non-toxic RV/marine antifreeze approved for potable-water systems, and only where the appliance manufacturer allows it. Never use automotive engine antifreeze in the drinking-water system.
• Do not exceed the pressure specified by the RV or appliance manufacturer if using compressed air. Some appliance pumps and valves can be damaged by air pressure or by running dry.

Step 1: Shut down and prepare the RV

1. Park the RV level in the place where it will be stored. Disconnect the city-water hose and turn off the water pump.
2. Turn off the water heater’s propane and electric heat sources. Let the water heater cool completely before draining it. Never drain a hot, pressurized water heater.
3. Drain the freshwater tank, water heater, low-point drains, and plumbing as directed by the RV manual. Put the water heater in bypass before introducing antifreeze to the RV plumbing, and remove or bypass water filters as instructed.
4. Choose the RV’s approved plumbing method: potable-water antifreeze or regulated compressed air. Follow the RV manufacturer’s procedure. Do not assume that blowing out the main water lines alone will empty an appliance’s pump, valve, or drain trap.

Step 2: Winterize the dishwasher

1. Empty and clean it. Remove dishes and food debris. Clean the filter and any removable screens according to the dishwasher manual.
2. Isolate the water supply. Close the appliance shutoff valve if fitted, or isolate the system using the RV’s approved procedure. Relieve water pressure before disconnecting any hose. Do not disconnect a pressurized line.
3. Use the dishwasher’s own winterizing procedure. If the manual provides a winterize mode or specific sequence, follow it exactly. Some models require draining the sump, inlet valve, or drain hose in a particular order.
4. Use antifreeze only if the manual explicitly permits it. Follow the specified product and amount. Do not pour antifreeze into the dishwasher tub, dispenser, pump, or drain unless the manufacturer says to do so. Some appliance materials and pumps are not designed for that method.
5. Protect the drain path. Follow the manual for the drain hose, check valve, and any shared sink trap. Water can remain in a low section of hose or trap even after the tub appears empty.

Step 3: Winterize the washer

1. Empty the machine. Remove laundry, empty and clean the dispenser, and wipe out the drum as directed by the washer manual.
2. Drain the pump and hoses. If the washer has an accessible drain-pump filter, open it slowly with towels and a shallow pan ready; residual water may spill out. Drain the inlet and drain hoses using the manufacturer’s instructions. Do not remove a filter or hose while the machine is hot, pressurized, or powered.
3. Run a built-in winterize cycle if provided. Follow the exact instructions for your model. If the procedure calls for RV antifreeze, use only an approved potable-water product and the specified cycle and quantity.
4. Protect valves and the drain connection. The washer’s inlet valves, pump, and standpipe or drain trap may hold water. Use only the model-approved method to clear or protect them. Do not assume that an empty drum means the washer is fully drained.

Step 4: Winterize the dryer separately

A vented dryer usually has no water supply, so it does not need plumbing antifreeze. Clean the lint screen and, when accessible and safe, the vent path. Keep antifreeze out of the dryer drum, lint duct, and exhaust vent.

A ventless condenser or heat-pump dryer may have a condensate tank, pump, or drain hose that holds water. Empty the tank and follow the dryer manual for draining the condensate system. For a washer-dryer combo, winterize the washer’s water system and the dryer’s condensate system as two separate procedures. Do not disconnect a gas connection yourself; follow the appliance instructions or use a qualified technician.

Step 5: Protect shared traps and check your work

1. Check the sink, washer, and other connected drain traps shown in your RV plumbing diagram. Add RV antifreeze to a trap only when the RV or appliance manual calls for it and specifies where it belongs.
2. Confirm that appliance doors, valves, hoses, and filters are left in the positions recommended by the manufacturer. If the manual recommends leaving a door ajar to dry, make sure it is secure and cannot swing while traveling.
3. Label the water-heater bypass and any closed appliance valves so you can restore them correctly in spring. Keep a brief checklist of what was drained and which winterizing method you used.
4. Before storage, verify that the pump and appliances are off and that no water remains in exposed hoses or drains. If a step is unclear, pause and ask an RV technician rather than guessing.

Step 6: Bring the system back into service in spring

Before using the RV again, restore appliance valves and the water-heater bypass according to the manuals. Flush and sanitize the potable-water system as directed by the RV manufacturer. Inspect every appliance connection for leaks, clean its filter, and run an empty test cycle only after the water supply is restored. Do not turn on an electric water heater until it is completely full and air has been purged from the system.

A safer winter starts with the right manual

Dishwashers and washer-dryers are not all winterized the same way. The safest process is to protect the RV’s plumbing, then follow the exact instructions for each appliance’s valves, pumps, hoses, and traps. The key rule is simple: never put antifreeze through an appliance or apply compressed air unless that specific manufacturer’s procedure allows it. A few minutes checking the model manual can prevent a costly spring repair.

Winterization checklist

• Water heater off, cool, drained, and bypassed as directed.
• Freshwater lines and filters winterized by the RV-approved method.
• Dishwasher filter, sump, supply valve, and drain path handled per its manual.
• Washer pump filter, inlet hoses, drain hose, and standpipe protected per its manual.
• Dryer lint screen and any condensate reservoir or drain handled per its manual.
• Only approved RV potable-water antifreeze used, and only where permitted.
• Valves labeled and the water heater kept off until refilled in spring.