If your RV is going to sit through freezing temperatures, winterizing is not optional. Done wrong, it means cracked fittings, busted water heaters, and expensive repair bills. Done right, it is just a methodical process you repeat every year. This guide walks you through the core steps: draining, blowing out lines, bypassing the water heater, adding RV antifreeze, and then reversing the process when you are ready to camp again.

Hey Happy Campers!

Todd here with Great American RV SuperStores.

Today, we are going over how to winterize your RV plumbing system.

We will cover:

• Draining water heaters, tanks, and lines
• Blowing out the plumbing with air
• Using water heater bypass valves
• Pumping RV or marine antifreeze through the system
• De-winterizing when the cold is gone

You may have a different layout than the one in the video, so always double check your owner’s manual for brand specific notes.

Step 1: Drain the Water Heaters

Different rigs use different water heaters, but the goal is always the same. Get the water out before you blow air or add antifreeze.

Furrion Tankless Water Heater

• Locate the Furrion tankless unit outside.
• At the bottom, you will see a drain port. Turn the plug counterclockwise to remove it.
• Make sure you have opened hot faucets inside first to relieve pressure.
• Let the unit drain completely and leave the drain open while you work.

Furrion tankless water heaters do not like high air pressure. Later, when you blow out the system, stay at or under 30 PSI.

Suburban and Dometic Tanked Water Heaters

• You will see a plastic plug or anode rod at the bottom center.
• Remove the plug or rod and let the tank drain out.
• Do not bypass the water heater yet if you still plan to blow the lines out.
• Once it is fully drained, you can leave the plug or rod out while the RV is in storage.

Truma Water Heater

• Open the exterior cover.
• Lift the small black tab and pull the yellow lever down.
• A filter assembly comes out and water drains from the internal reservoir.
• Let it drain fully, then clean the little filter screen if you want.
• When done, reinstall the filter with the “top” indicator facing up and click it back in.

For Truma, especially, follow their manual carefully. They are particular about winterization steps.

Step 2: Remove Filters and Open Faucets

If your RV has a whole house filter:

• Unscrew the filter housing.
• Remove the filter cartridge and set it aside or discard it.
• Reinstall the empty housing.

Then:

• Open every faucet in the RV. Hot and cold, at all sinks and showers.
• Open any outside shower, spray port, or utility faucet.

You are letting air into the system so it can drain freely.

Step 3: Open Low Point Drains and Tank Drains

Find your low point drains:

• Usually one red line (hot) and one blue line (cold) with small valves.
• On motorhomes they are often in the water bay.
• On travel trailers they may hang below the frame or under the belly.

Steps:

1. Open the hot and cold low point drains and let them run until they stop.
2. Open the fresh tank drain and empty the fresh tank.
3. Drain your gray and black tanks as well.

Once everything has stopped draining, close:

• All faucets
• All low point drain valves
• All tank drain valves
• Fresh water tank

There will still be some water in elbows and low spots, so the next step is the air compressor.

Step 4: Blow Out the Plumbing With Air

Find your city water connection. This is where we will hook in air.

You have two main options.

Option A: Two Person Air Chuck Setup

Use a fitting that:

• Screws into the city water connection
• Has a tire valve style tip on the other end

Steps:

1. Screw the fitting into the city water inlet.
2. Set your compressor regulator to 30 PSI maximum.
3. Optional: install a 30 PSI water pressure regulator in line for extra safety.
4. One person holds an air chuck on the tire valve end.
5. The other person goes fixture to fixture in the RV.
6. Open each faucet until only air and light mist come out, then close it.
7. Do hot and cold on all faucets, outside showers, spray ports, and the toilet.
8. Finish by opening the low point drains again and the water heater relief or drain so air can clear those areas too.

Option B: One Person Quick Connect Setup

Use a fitting that:

• Screws into the city water connection
• Has a quick connect for your air hose on the back

Steps:

1. Screw the fitting into the city water inlet.
2. Set your compressor to 30 PSI.
3. Connect the air hose.
4. Walk through the RV, opening each faucet and fixture one at a time until only air comes out.
5. Open low point drains and water heater drain or high pressure relief and let air push the last of the water out.

Do not exceed 30 PSI. High pressure can damage seals inside your water heater or fittings.

Step 5: Check Filter Housing and Set Water Heater Bypass

After blowing the system out:

• Recheck the filter housing. Empty any water still trapped in it.
• Now find your water heater bypass valves.

On a typical tanked water heater, when you remove the access panel on the back, you will see:

• A cold water line into the bottom
• A hot water line out the top
• A bypass loop connecting the two

Turn the valves so that water and antifreeze flow around the tank instead of into it. That way, you do not waste gallons of antifreeze filling a tank you do not need full in storage.

Leave the drain plug or anode rod out of the water heater while the RV is winterized.

Step 6: Pump RV Antifreeze Through the System

Now that you have drained and blown everything out, it is time for RV or marine antifreeze. Do not use automotive antifreeze in your plumbing system.

Common setups:

A. Pump With Built In Winterization Valve

Most modern towables have:

• A water pump with a small inlet screen
• A third suction line and valve with a loose hose for antifreeze

Steps:

1. Locate the water pump. Turn it on briefly and listen if you need help finding it.
2. Remove and empty the small inlet screen, then reinstall it.
3. Find the loose winterization hose and its valve.
4. Put the loose hose into a jug of RV antifreeze.
5. Turn the valve so the pump draws from the antifreeze hose instead of the fresh tank.
6. Turn on the pump.
7. Go to each faucet and open it until solid pink antifreeze comes out, then close it. Do hot and cold.
8. Do outside showers, spray ports, and the toilet.

As the antifreeze runs, some will go into each P trap. If you want extra protection, you can pour a little additional antifreeze directly into each sink and shower drain.

Leave gray and black tank valves closed. A little antifreeze will collect near the valves and help protect them.

B. Conversion Kit at the Pump

If your pump has no winterization tee and only a straight suction line:

• Install a winterization conversion kit that adds a tee and a third line with a valve and hose.
• Cut into the suction line before the inlet screen.
• Install the tee and attach the winterizing hose.

From there, you use it exactly like setup A.

Some motorhomes, like many Tiffin units, come with a loose hose intended to thread onto the pump inlet. In that case, you remove the standard hose, install the winterization hose, stick it in the antifreeze, and run the pump. A permanent tee is easier if you do this every year.

C. Valve Manifold Systems (Jayco, Grand Design, Tiffin and others)

Many fifth wheels and motorhomes have a valve panel with labeled positions, such as normal, sanitize, and winterize.

Typical pattern:

1. Set the valves to the winterize or sanitize/winterize configuration shown on the panel.
2. Attach a short hose from the labeled port (or city water inlet, depending on the design) into your antifreeze jug.
3. Turn on the pump.
4. Go faucet by faucet until pink antifreeze appears, just like in the previous setups.
5. Do not forget outside fixtures and the toilet.

The idea is the same. The panel just replaces the tee at the pump.

Step 7: De-winterizing Your RV

When you are ready to camp again:

1. Hook a fresh water hose to your city water connection.
2. Turn on the spigot.
3. Go through the RV and run each faucet until the water runs clear and all the pink is gone.
4. Flush the toilet and outside fixtures until they are clear as well.
5. If you bypassed the water heater, reinstall the plug or anode rod and turn the bypass valves back to normal so the tank can fill.
6. Let the tank completely fill before turning on gas or electric heat. Running a dry water heater will damage elements and components.
7. Open low point drains and drain out until all the pink is gone.

Once everything is flushed and the water heater is full, you are ready to camp again.

What If It Only Freezes Occasionally?

If you live in a mild climate and only see an occasional hard freeze, many owners:

• Drain the system
• Blow the lines out with air
• Skip the antifreeze in the plumbing

If you choose that route, pay attention to the weak spots:

• The toilet foot pedal valve likes to trap water and crack. The safest move is to disconnect the water line at the valve and let water drain out of it.
• The filter housing will hold water at the bottom unless you open and empty it.
• Any low point that acts like a trap can still hold enough water to freeze.

Air only is always a bit of a gamble. Full RV antifreeze winterization is the safer choice if you know you will see several nights below freezing.

Final Thoughts

Winterization feels like a lot the first time, because every brand hides valves and pumps in different places, but the pattern never really changes.

Drain it, blow it out, bypass what you do not want to fill, then pump RV antifreeze through everything else.

If you are not sure where your pump, low point drains, or bypass valves are, bring your unit by any Great American RV SuperStores location. We can walk you through it or handle the full winterization for you.

For a visual walkthrough, check out the winterization episode in our Hap’s Helpful Hacks playlist on the Great American RV YouTube channel.

Here at Great American RV SuperStores, we bring the how to to you.

*This content is not a legal standard or regulation, and does not create any new legal obligation.  It is advisory in nature, informational in content, and is intended to assist and educate consumers in the use and enjoyment of their recreational vehicles.  Great American RV SuperStores does not hereby make any warranty, express or implied, and does not assume any liability with respect to the use of, or damages resulting from the use of any information, method or process included in this content.