The Complete RV Winterization Checklist: Start to Finish

Before You Start

Supplies, Setup, and Why Order Matters

Here's what I see in the field every spring: owners who winterized their own RV, did most of it right, and still ended up with a problem because they did one step out of sequence or skipped one step entirely. A cracked P-trap. An antifreeze-filled water heater tank that wasted 8 gallons of product. A battery that won't take a charge because it sat discharged all winter.

The sequence matters. Each step in this guide follows the one before it for a reason. Do them in order and you won't miss anything.

🔧 What You'll Need

Item	Notes	Est. Cost
Non-toxic RV antifreeze (pink)	Propylene glycol, rated for potable water. NOT automotive antifreeze.	$4–$6/gal
RV winterization kit	Connects your water pump to draw directly from the antifreeze jug. Separate from the water heater bypass.	$10–$20
Battery maintainer	For storage — keeps battery topped off without overcharging	$25–$60
Basic hand tools	For drain plugs (water heater anode or plug)	Already have
Rags or paper towels	Antifreeze drips during the process	Already have
Roof sealant (as needed)	Self-leveling for horizontal surfaces, non-leveling for vertical	$8–$15/tube

🚫

Never Use Automotive Antifreeze in an RV Water System

Automotive antifreeze is ethylene glycol-based and toxic. RV antifreeze is propylene glycol-based and non-toxic. The labels look similar at a glance. Read carefully before you buy. The label must say "non-toxic" and "RV and marine" to be safe for your water system.

Remove any inline water filters before you start. Pull the cartridges and bypass the filter housings. Pumping antifreeze through a filter cartridge wastes the cartridge and doesn't protect it.

Step 1

Bypass the Water Heater

This is the first step. Do this before you drain anything or touch the water pump.

The water heater bypass routes water around the tank so antifreeze flows through the rest of your plumbing without entering the tank. A standard tank holds 6 to 10 gallons. Without the bypass set, every drop of that tank volume gets filled with antifreeze. That's expensive and completely unnecessary. With the bypass set, the tank stays dry and protected.

1

Locate the water heater bypass valves

Usually found behind the water heater exterior access panel or inside a cabinet adjacent to the water heater. Most setups use two or three manual shutoff valves. Some RVs have a single-lever bypass. If you can't find yours, check the owner's manual before proceeding.

🚨

Turn the Water Heater Off Before You Empty It

Gas switch off. Electric element switch off. Both. Then open a hot water faucet inside the RV to relieve line pressure before you touch the anode rod or drain plug. Removing a drain plug from a hot, pressurized tank is a serious burn hazard. Let it cool first. This step is not optional.

2

Drain the water heater tank

Once the heater is off, cooled, and pressure is relieved, open the exterior access panel. Remove the anode rod (Suburban tanks — 1-1/16" socket) or drain plug (Atwood/Dometic tanks — 15/16" socket). Let the tank drain fully. The drain opening sits higher than the tank bottom, so some water remains — that's fine once the bypass is set and the tank is isolated.

3

Set the water heater bypass

Turn the valves to the bypass position. The exact positions vary — consult your owner's manual if you're unsure. The goal is to isolate the tank completely so water and antifreeze flow through the hot water lines without entering the tank.

4

Mark it visibly

Tape a note on the water heater access panel: "WATER HEATER BYPASSED — RESET BEFORE USE." The most common spring startup mistake is turning on the water heater before resetting the kit. A note prevents it.

⚠️

Hydronic and Aqua-Hot Systems: Different Rules Apply

If your RV has an Aqua-Hot or similar hydronic heating system, the domestic hot water coil must have antifreeze pumped through it. Air blow-out and draining alone will not protect it. Failure of the domestic hot water coil in these systems is catastrophic and not covered under warranty. If you have one of these systems and haven't winterized it before, call a tech.

Step 2

Drain the System

With the water heater bypassed, drain all water out of the main system before you pump antifreeze in. This reduces how much antifreeze you need and removes as much water as possible from the lines.

🔧 Drain Sequence — Do These in Order

Turn off the water pump and disconnect from city water. Relieve any remaining line pressure by opening a faucet until flow stops.

Drain the fresh water tank. Open the fresh water tank drain (usually a valve or cap under the RV) and let it empty completely.

Open the low-point drains. These are usually two separate drains near the low point of the water system — one for hot lines, one for cold. Open both. Let water run until it slows to a drip.

Open all faucets. Inside and outside. Hot and cold both. Leave them open during the drain step.

Flush the toilet. Hold the pedal until the bowl is clear.

Drain and flush holding tanks. Black and gray tanks should be drained and rinsed before long-term storage.

💡

Lubricate the Termination Valves While You're There

When the tanks are empty and you're working at the termination valves, apply a thin coat of RV-rated valve lubricant to the blade valves. Valves that sit closed all winter without lubrication can seize by spring. A stuck valve during dump station season is an unpleasant problem. Two minutes now prevents it.

Step 3 — Optional but Recommended

Blow Out the Lines With Air First

Most owners skip straight from draining to antifreeze. The more thorough approach is to blow the lines out with compressed air first, then follow with antifreeze. The air removes the bulk of the water sitting in the lines. The antifreeze then coats the lines, valves, and seals with a protective layer — catching what the air couldn't reach. Together, the two methods cover each other's gaps.

Antifreeze alone is reliable. Air alone has too many variables — not all RVs are built the same, and what works in one climate or underbelly configuration doesn't always work in another. Combining both is the safest approach, especially in climates that see hard, sustained freezes.

🚨

Cap Air Pressure at 40–50 PSI Maximum

Exceeding 50 PSI can damage fittings, valves, and seals inside the water system. Set your regulator before you connect to the city water inlet. Never use shop air at full pressure. RV plumbing is not built for it.

1

Set the air pressure to 40–50 PSI at the regulator

Connect a blow-out plug to your air compressor and set the pressure before attaching it to the RV. Do not connect first and then adjust — you want the pressure controlled before it enters the system.

2

Connect to the city water inlet

Thread the blow-out plug into the city water inlet on the exterior of the RV. Keep the water pump switch off during the blow-out — you're using air pressure from outside, not the pump.

3

Open each fixture one at a time

Work through the fixtures starting with the farthest from the inlet. Open the hot side of each faucet, let air blow through until the spray is dry and minimal, then close it. Repeat on the cold side. Move to the next fixture. Don't try to blow multiple fixtures open at once — you lose pressure and coverage.

4

Run the toilet and exterior outlets

Flush the toilet while air pressure is active. Hold until the spray clears. Run the outside shower and any exterior outlets the same way.

⚠️

Air Alone Doesn't Protect P-Traps or Seals

P-traps hold water by design and can't be blown out — they need antifreeze poured directly down every drain regardless of what else you do. Air blow-out also doesn't protect pump seals and some valve seals the way antifreeze does. Always follow the blow-out with antifreeze through the RV winterization kit. Don't treat air as the complete method.

Step 4

Pump In Antifreeze

Close the low-point drains and all faucets. Connect the RV winterization kit to the pump inlet and drop the tubing into your antifreeze jug. You're ready to push antifreeze through the system.

There are two ways to get antifreeze into your water system. The first uses an RV winterization kit — a piece of tubing that connects to the inlet side of your water pump so the pump draws directly from the antifreeze jug instead of the fresh water tank. The second uses a dedicated winterizing connection at the city water inlet if your RV has one. The RV winterization kit is the most reliable method for most setups.

1

Connect the RV winterization kit to the pump inlet

Disconnect the water supply line from the inlet side of the pump. Attach the kit tubing to the pump inlet and drop the other end into your first jug of antifreeze. Make sure the jug is upright and stable.

2

Start at the farthest fixture and work back

Turn on the water pump. Go to the fixture farthest from the pump first. This pushes air out of the lines ahead of the antifreeze. Open the hot side, then the cold side at each faucet. Run until you see steady pink coming from both. Close that faucet. Move to the next farthest fixture. Repeat until you've covered every faucet inside the RV.

3

Run the toilet

Flush the toilet and hold until pink antifreeze fills the bowl and the lines. This protects the valve and the supply line to the toilet.

4

Run every exterior faucet and outdoor shower

This is the step most owners rush or skip entirely. Every outdoor water connection has its own supply line running to the exterior — often through an unheated compartment or along an exposed wall. Those lines freeze just as easily as the lines inside.

Run each one until you see steady pink antifreeze at the outlet. That includes the outside shower, any exterior kitchen faucet, utility sink, and any other outdoor water connection. Don't assume antifreeze reached them from the inside sequence — exterior lines often branch off separately and need to be run individually to confirm coverage.

⚠️

Outdoor Faucets and Showers Are the Most Commonly Missed

Exterior water connections are out of sight and easy to forget. The outside shower, exterior kitchen faucet, and any outdoor utility connections all have supply lines that freeze. If you don't run antifreeze through each one until you see pink at the outlet, that line still has water in it — and that water will freeze. The repair is the same as any other frozen line: cracked fittings, valves, or pipe sections to replace in spring.

5

Ice maker, dishwasher, or washing machine

These appliances have their own internal water circuits and must be winterized separately. Each has a specific procedure depending on the unit. If you're not sure how to do this for your specific appliance, this is a step worth getting help with. An improperly winterized washing machine or ice maker can crack internal components that are expensive to replace.

💧

Watch Your Antifreeze Levels

Keep an eye on the jug as you work. If the pump starts pulling air, it will lose prime and you'll need to reprime before continuing. Most systems need 2 to 3 gallons with the water heater bypassed. Have an extra jug on hand.

Step 4

Protect the P-Traps

This step gets skipped more than almost any other. The water pump sequence gets antifreeze into your supply lines. It does not get antifreeze into your P-traps.

P-traps are the curved sections of drain pipe under every sink, shower, and floor drain. They hold a small amount of water by design to block sewer gases from entering the RV. That water sits there all winter. If temperatures drop hard enough, it freezes. Frozen water expands. P-traps crack.

🔧 P-Trap Antifreeze — Every Drain

Kitchen sink: Pour a small amount of RV antifreeze directly down the drain. You don't need much — just enough to displace the water in the trap and coat it with antifreeze.

Bathroom sink: Same — pour antifreeze directly down the drain.

Shower drain: Pour directly down the floor drain.

Any floor drains: These are easy to miss. Check every room.

Outside shower: If it has a drain, treat it.

Step 5

Battery Storage

A fully charged lead-acid battery can survive most winter storage conditions. A discharged battery freezes at 32°F. That's the whole story.

Before you leave the RV for storage, check the battery voltage with a multimeter. A fully charged 12-volt battery reads 12.6 volts or above with no loads on it and having not been charged for at least an hour. Anything below 12.4 means it needs to be charged before storage.

1

Charge the battery fully

Bring it to 12.6V or above before storage. Don't skip this step and assume the converter will take care of it — the converter needs shore power connected and a proper multi-stage charging mode to be reliable for storage maintenance.

2

Clean the terminals

Clean any corrosion from the terminals before storage. A mixture of baking soda and water neutralizes corrosion buildup. Dry thoroughly. Apply a light coat of dielectric grease to the connections.

3

Choose your storage method

Option A: Disconnect the battery and store it somewhere with stable temperatures (a garage, conditioned space). Check voltage periodically and charge if it drops below 12.4V. Option B: Leave the battery in the RV connected to a battery maintainer (not a trickle charger — a smart maintainer) that keeps it topped off. Either method works. Doing nothing is the option that fails.

⚠️

Turn Off the Electric Water Heater Element

If you're leaving the RV connected to shore power during storage, make sure the water heater electric element is switched off. Running the element in a drained, bypassed tank damages or destroys it. Check the water heater control switch inside the RV and confirm it's in the off position.

Step 6

Roof, Seals, and Exterior

Before the RV goes into storage, do a roof and seal inspection. This is one of the two times a year this inspection matters most — fall before storage and spring at startup. Freeze-thaw cycles crack sealant. Any failed seal that you don't catch now will let water in all winter.

🔧 Roof and Exterior Checklist

Walk the roof and check every seam. Vents, air conditioner base, front cap, rear cap, antennas, and satellite mounts. Press gently on the sealant at each point. Good sealant is still flexible. Cracked, hard, or separating sealant needs to be addressed before storage.

Check slide seals from the ground. Look for cracks, tears, or compressed areas where the wiper seals have lost their shape. Damaged slide seals let water track inside the slide pocket over winter.

Check window and door gaskets. Squeeze them. They should spring back. Hard, cracked gaskets that won't flex are no longer sealing properly.

Apply sealant where needed. Use self-leveling Dicor for flat horizontal surfaces on rubber roofs. Use non-leveling for vertical joints and corners. Let it cure before rain hits the RV.

Cover the tires if stored outdoors. UV degrades rubber over time. Tire covers extend life and reduce sidewall cracking from sun exposure during long storage periods.

Cover or plug exterior openings for pests. Furnace exhaust, refrigerator vents, and water heater vents are common entry points for mice and insects over winter. Mesh screens or foam plugs (removed before startup) work well.

🚨

Roof Work: Don't Go Up Alone

If you need to access the roof, have someone with you. RV roofs vary significantly in how much weight they can support and where. Know your roof type and safe walking areas before you step up. If the roof inspection can be done from a ladder at the roofline, that's often the safer approach.

Step 7

Final Steps and Documentation

The last ten minutes of winterization are the ones that save you in spring. Don't rush them.

✅ Final Winterization Steps

Turn off all propane valves at the tanks. Don't leave propane on during storage.

Turn off the water heater electric element switch. Confirm it's off at the interior panel.

Run the generator briefly to exercise it, then add fuel stabilizer if it's stored with fuel in the tank. Stale fuel is the primary reason stored generators won't start in spring.

Crack the ceiling vents slightly. A small amount of airflow prevents moisture buildup and reduces mold risk during storage. Don't leave them fully open in climates with heavy snow.

Remove perishable food and clean the interior. Any moisture source left in the RV — wet sponges, open food, damp towels — becomes a mold source over a long storage period.

Prop the refrigerator door open. With the power off, the fridge needs airflow to prevent mold and odors. A small spacer between the door and the frame works. Leave a box of baking soda inside.

Check and record tire pressure. Inflate to the correct cold pressure before storage. Tires lose pressure slowly over time and sitting on underinflated tires creates sidewall stress.

Write down what you did and when. Note the date, the antifreeze method used, and any issues you found. This log helps you at spring startup and creates a maintenance history if you ever sell the RV.

"The sequence is everything. I've seen owners who did every step correctly but in the wrong order and ended up with antifreeze in a tank they meant to bypass, or a battery that discharged before they got the maintainer connected. Do it in order, document what you did, and your spring startup becomes an hour of routine work instead of a diagnosis appointment."

— Marvin Kennedy, RVTI Level 4 Master Certified RV Technician

Quick Reference

The Complete Winterization Checklist

Use this as your walkthrough. Every item in order.

🏁 Before You Start

Remove inline water filters and bypass filter housings

Gather supplies: non-toxic RV antifreeze (pink), RV winterization kit, tools for anode/plug

Disconnect from shore power and city water

Step 1: Set the Water Heater Bypass

Turn off the water heater — gas AND electric — before touching anything. Open a hot faucet to relieve pressure.

Drain the water heater tank (remove anode rod or drain plug once cooled and depressurized)

Set the water heater bypass valves to isolate the water heater tank

Leave a visible note: "WINTERIZATION KIT SET — RESET BEFORE USE"

Step 2: Drain the System

Turn off water pump

Drain fresh water tank

Open low-point drains (hot and cold)

Open all faucets (hot and cold), flush toilet

Drain and flush holding tanks

Lubricate termination valves while accessible

Step 3: Blow Out Lines With Air (Optional but Recommended)

Set air pressure to 40–50 PSI max at the regulator before connecting

Connect blow-out plug to city water inlet — water pump OFF

Work farthest fixture to nearest — hot then cold at each until spray runs dry

Run toilet and all exterior outlets until clear

Follow immediately with antifreeze — air alone is not a complete winterization

Step 4: Pump In Antifreeze

Close low-point drains and all faucets

Connect RV winterization kit to pump inlet, drop into antifreeze jug

Work farthest fixture to nearest — run each until pink appears (hot and cold)

Flush toilet until pink fills bowl

Run every exterior faucet, outdoor shower, and outside utility connection — confirm pink at each outlet

Winterize appliances (ice maker, washer, dishwasher) per their procedures

Step 4: Protect the P-Traps

Pour antifreeze directly down every sink drain

Pour antifreeze down the shower drain

Pour antifreeze down any floor drains

Pour antifreeze down outside shower drain (if applicable)

Step 5: Battery Storage

Check battery voltage (12.6V+ for full charge)

Charge to full if below 12.4V

Clean terminals — remove corrosion, apply dielectric grease

Connect battery maintainer OR disconnect and store in conditioned space

Step 6: Roof, Seals, and Exterior

Inspect all roof seams, vent bases, and penetrations

Apply sealant where cracked, separated, or missing

Check slide seals and window gaskets

Cover tires (if stored outdoors)

Cover or plug exterior vents for pest prevention

Step 7: Final Steps

Turn off propane at the tanks

Confirm water heater electric element is off

Exercise generator, add fuel stabilizer

Crack ceiling vents for airflow

Remove food, clean interior

Prop fridge doors open with baking soda inside

Check and record tire pressure

Document date, method, and any issues found

Section 10

When to Stop and Call a Tech

Most RVs with standard water systems can be winterized by their owners following this guide. But there are situations where calling a certified technician is the right call.

🔧 Call a Tech If Any of These Apply

Hydronic or Aqua-Hot system present: These require antifreeze pumped through the domestic hot water coil. Air or drain methods alone will not protect them and the failure is unwarrantable and irreparable.

Tankless water heater: Procedures differ from tank-type units. Confirm the correct process for your specific model before proceeding.

You can't locate the water heater bypass: Don't guess. A tech can locate it and walk you through the process for next year.

You had a freeze event last year: Have the system inspected before winterizing again. Pumping antifreeze through a damaged line distributes the problem.

You're unsure about any appliance procedure: Ice makers, dishwashers, and washing machines have specific winterization steps. Doing it wrong means a cracked appliance come spring.

The companion article to this one covers the top three winterization mistakes in detail, including why each one happens and what the repairs actually cost: The Top 3 RV Winterization Mistakes That Cost Owners Thousands.

It's quicker and less expensive to winterize correctly now than to repair freeze damage in spring.