❄️ Part 6: Winterizing Your Casita

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The thought of winterizing a camper gives a lot of new owners anxiety. They picture frozen, burst pipes, flooded floors, and massive repair bills. But here is the comforting truth: winterizing is just a simple, logical system of removing water so ice can’t expand and break things. Once you learn the routine, it takes less than 20 minutes and costs very little.

There are two distinct ways to winterize your Casita: blowing the lines completely clear using compressed air, or pumping non-toxic pink RV antifreeze through the pipes. Both work beautifully, so you can choose the method you feel most comfortable with.

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Method 1: The Blowout Routine (No Chemicals)

If you prefer not to introduce RV antifreeze into your fresh water plumbing, this is your best option. You will need a small brass “RV Blowout Plug” (an inexpensive adapter with a Schrader tire valve that screws into your City Water inlet) and a low-pressure portable tire pump.

• Step 1: Drain the Fresh Water Tank – Open your fresh water tank drain valve underneath the trailer to let the main tank empty completely.
• Step 2: Bypass the Water Heater – Go inside the trailer and locate the water heater compartment. Turn the brass bypass lever to isolate the water heater tank from the rest of the plumbing lines.
• Step 3: Open Faucets & Hook Up Air – Open the hot and cold faucets in the bathroom. Head outside and screw your brass blowout plug into the City Water inlet, then connect your low-pressure cigarette-lighter-style tire pump to the Schrader valve on the brass blowout plug.
• Step 4: Purge the Plumbing Lines – Turn on the tire pump. Go inside and follow this sequence to clear the lines:
• Wait for the water to stop coming out of the open bathroom faucets and turn them off.
• Hold down the toilet flush valve until all water is completely expelled from the toilet lines.
• Move to the kitchen sink, turn on both the hot and cold faucets, and wait until they run completely dry.
• Step 5: Disconnect the Pump – Go outside, turn off the tire pump, disconnect it from the valve, and remove your blowout plug.
• Step 6: Drain and Clean the Water Pump – Go back inside the trailer to the bottom cabinet where the water pump is located. Place a towel underneath the pump to catch any spills. Disconnect the blue quick-release clips on each side of the pump to ensure all trapped water drains completely out. While you have it open, inspect the plastic filter screen on the intake side of the pump and clean out any debris.
• Step 7: Protect the P-Traps – Even with the lines dry, pour about one cup of pink RV antifreeze down your kitchen sink drain, bathroom drain, and shower drain to protect the P-traps, and leave a small amount in the toilet bowl to keep the seal lubricated.
• 🛑 CRITICAL COMPRESSOR WARNING: Never connect an unregulated shop air compressor directly to your RV plumbing. Many shop compressors produce 90–150 PSI—far more pressure than RV plumbing is designed to handle. Always regulate the pressure to 30–40 PSI before connecting it to your trailer to prevent blowing your plumbing connections apart behind your fiberglass walls. Commercial compressors can also introduce tiny amounts of oil vapor into clean drinking lines if unregulated.

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Method 2: The Pink Flush Routine

For absolute peace of mind without needing an air compressor, using non-toxic RV antifreeze is a bulletproof method.

⭐ The Road Ready Winterizing Rule: Never use automotive antifreeze in your fresh water plumbing lines. Only use non-toxic, pink RV Antifreeze (specifically labeled safe for potable water systems).

• Step 1: Drain and Bypass – Follow Steps 1 and 2 from the blowout method above to empty your tanks, let the water heater cool down, and bypass the heater tank. (If you forget to bypass the heater, you’ll waste six gallons of antifreeze filling a tank that doesn’t need it!)
• Step 2: Connect to the Antifreeze – Since Casitas do not have a factory-installed siphon tube, you have two options to get the antifreeze into your lines:
  a. The Pump Intake Method: Go to your water pump under the cabinet. Disconnect the blue quick-release clip on the intake side (the side coming from the fresh water tank). Connect a spare piece of tight-fitting vinyl tubing to that intake port and drop the other end directly into your jug of pink RV antifreeze.
  b. The Fresh Tank Method: Alternatively, ensure your fresh tank is completely drained, then pour 2 to 3 gallons of pink RV antifreeze directly into your exterior gravity water fill hatch.
• Step 3: Pump the Pink – Turn on your 12V water pump inside. Go to your kitchen sink and open the cold faucet until bright pink liquid flows out, then switch to the hot side until it runs pink. Repeat this exact step for the bathroom sink, toilet valve, toilet sprayer, indoor shower, and outdoor shower.
• Step 4: Protect the Traps – Turn off the pump. Pour one remaining cup of pink antifreeze down each drain (kitchen, bathroom, shower) and into the toilet bowl to protect the traps and rubber toilet seal.

🏕️ Road Ready Tip: The City Water Check

Whichever method you choose, there is one tiny valve that almost everyone forgets. Go outside to your City Water Connection inlet, remove the screen, and gently press the little white button inside using a pen or screwdriver for just a split second while the system is pressurized (either by air or the pump). Stand to the side! A tiny splash of water or pink antifreeze will squirt out, confirming the inlet check-valve is safe from freezing.

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⚠️ Common Winterizing Mistakes

• Forgetting to let the water heater cool down before pulling the drain plug.
• Forgetting to bypass the water heater, resulting in accidentally wasting six gallons of antifreeze.
• Blasting the water lines with unregulated or high-pressure air (Keep it under 40 PSI!).
• Leaving water sitting in the toilet sprayer or outdoor shower hose. These thin plastic components will crack instantly if water freezes inside them.
• Forgetting to remove any inline drinking water filter cartridges before winterizing.

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✅ The Winterization Checklist

Before leaving your Casita for the freezing winter months, verify this list:

☐ Water heater turned OFF, allowed to cool, drained, and bypassed
☐ Fresh water tank and low-point drains emptied and closed
☐ Inline water filter cartridges removed
☐ Traps protected (Pink antifreeze poured into kitchen, shower, and bathroom drains)
☐ Air blowout pressure kept strictly between 30–40 PSI (If using Method 1)
☐ Antifreeze visible at every single hot and cold faucet outlet (If using Method 2)
☐ City water inlet valve cleared of trapped water
☐ All interior faucets left slightly cracked open to relieve residual pressure

Congratulations! The job that worries almost every new RV owner is officially done, and your Casita is completely protected until spring.

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🤝 Help the Next Casita Owner

The best camping tips come from real Casita owners.

If you’ve discovered a better technique, noticed something we should improve, or have an idea that could make this guide even better, we’d love to hear from you.

Every suggestion is personally reviewed, and the best ideas help improve Road Ready Casita for future owners.

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