How to Winterize Your RV for Storage (2025 Update): Step-by-Step + When to Use Extreme Cleaner

How to Winterize Your RV for Storage (2025 Update): Step-by-Step + When to Use Extreme Cleaner

Posted by RVCampersUSA on Sep 22nd 2025

How to Winterize Your RV for Storage (2025 Update): Step-by-Step + When to Use Extreme Cleaner

Winter is coming—and a careful winterizing routine can save you thousands in cracked fittings, burst lines, and nasty spring odors. This fully updated guide walks you through the exact steps to winterize your RV’s plumbing and tanks, clarifies the best timing for Happy Campers Extreme Cleaner, and explains why you should never dump Extreme into a home septic system (but it’s fine at approved RV dump stations). We’ve also included our Top 10 Winterizing Products with links so you can check everything off in one pass.

Short answer: Winterize now using RV antifreeze and standard holding tank treatment for odor control. Save Extreme Cleaner for your spring tank reset: add it with fresh water before your first drive, then dump and flush at an approved RV dump site (not home septic).

Why Winterizing Matters

Any water left in lines, fittings, traps, or appliances can freeze, expand, and cause cracks or leaks. Even if temperatures only dip on a few nights, the wrong pocket of water in the wrong place can make a mess of spring startup. Proper winterizing also prevents odor issues and residue that can mislead sensors or feed bacteria growth while your rig is stored.

Storage myth: “I drained my tanks so I’m good.” — Not quite. Residual moisture sits in low points and traps. You’ll still need to blow out lines or displace with RV antifreeze, protect the water pump, and prep your tanks for months of inactivity.

Winterizing Overview (What You’ll Do)

1) Drain & Flush Tanks

Empty black, gray, and fresh tanks. Rinse thoroughly. Add a final dose of Happy Campers Holding Tank Treatment with your last flush to keep odors down over winter.

2) Clear Water Lines

Blow out lines (compressed air) or displace with RV antifreeze. Bypass and drain the water heater.

3) Protect Fixtures & Pump

Pour RV antifreeze into every P-trap and the toilet bowl. Draw antifreeze through the water pump (per manual).

4) Seal, Store & Monitor

Close vents, deter rodents, manage interior moisture, protect tires, and re-check after the first cold snap.

Important: Do not use Extreme Cleaner during winterizing. It needs a thorough, fresh-water flush you can’t perform once the RV is put away. Use it for your spring tank reset (details below).

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RV winterizing infographic: Drain & flush, antifreeze, Extreme Cleaner timing, and storage tips

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Step-by-Step: How to Winterize Your RV

Step 1 — Drain & Flush All Tanks

Start with a full dump and rinse of your black and gray tanks. If your sensors misread or you’ve had odor issues, give tanks an extra rinse to reduce residue left over winter. Drain your fresh water tank and run the pump briefly (don’t dry-run) to push out remaining water.

  • Dump black first, then gray (to help rinse the hose).
  • Use a hose support to keep a steady downward slope.
  • Rinse using your built-in flush or a rinser wand.
Before you button up, add a final dose of Happy Campers Holding Tank Treatment with a small amount of fresh water and cycle it through the black and gray tanks. This helps control odor during storage and is gentle on seals.

Related reading: How to Dump & Flush Your RV Black Tank • Treatments vs. Cleaners

Step 2 — Water Heater: Bypass & Drain

Switch your water heater to bypass (so you don’t waste gallons of RV antifreeze filling the heater). Let the heater cool, open the drain/plug (and relief valve if needed) to empty it. Inspect the anode rod if applicable.

Step 3 — Clear Water Lines (Two Methods)

Method A: Compressed Air Blow-Out

  • Use a blow-out plug at the city water inlet; set compressor to ~30–40 PSI.
  • Open faucets one at a time (hot then cold) from highest to lowest points until they sputter air.
  • Don’t forget outside shower, washer hookups, toilet sprayer, low-point drains.

Method B: RV Antifreeze Displacement

  • Bypass the water heater first.
  • Insert the winterizing suction tube into RV antifreeze or use a hand pump at the city water connection.
  • Open each fixture until pink fluid appears; repeat for all lines and appliances listed above.
Which method is better? Blow-out is quick and tidy; antifreeze provides extra freeze protection and peace of mind. In very cold climates, many RVers do both.

Step 4 — Protect Traps, Toilet & Pump

  • Pour ~1 cup of RV antifreeze into every sink and shower drain to protect P-traps.
  • Add antifreeze to the toilet bowl to protect the seal and prevent evaporation.
  • Follow your pump’s instructions to draw antifreeze through the pump (or use air blow-out if you prefer).

Step 5 — Exterior & Interior Prep

Exterior

  • Seal obvious gaps; close roof vents (leave tiny airflow if recommended).
  • Cover tires or roll to prevent flat spots; maintain proper pressure.
  • Rodent deterrents around entry points; remove nesting materials.

Interior

  • Remove food; wipe down fridge and leave door cracked.
  • Open cabinet doors for air circulation; set moisture absorbers.
  • Turn off breakers per manual; confirm battery storage plan.
Pro tip: Do a quick walk-around after your first freeze. If you see pink drips, you’ve protected the right places.

Watch: This quick video shows how to properly winterize your RV step by step — from draining and flushing to adding RV antifreeze. Watch on YouTube

When to Use Extreme Cleaner (and Why Not in Home Septic Systems)

Happy Campers Extreme Cleaner is a powerful, industrial-strength cleaner designed to strip layers of buildup (including grease, biofilm, and hardened deposits) from RV tanks and internal surfaces. It’s highly effective for a seasonal tank reset and for stubborn problems like sensor misreads from residue on tank walls.

Timing: Use in Spring, Not During Winterizing

  • Don’t add Extreme Cleaner just before storage. You won’t be able to drive, agitate, and perform the thorough fresh-water flush it requires.
  • Do add Extreme Cleaner with fresh water before your first spring trip. Drive to your first destination so the solution can slosh, then dump and rinse thoroughly at an approved RV dump station.

Why Not in Home Septic?

Home septic systems are living ecosystems that rely on a balanced bacterial community to break down waste. Potent, alkaline, grease-cutting cleaners (like Extreme) can disrupt that balance if repeatedly introduced, potentially slowing breakdown and leading to system issues.

Bottom line: Use Extreme responsibly and always empty at a proper RV dump station or municipal facility designed to handle stronger cleaning agents.

Still Want Odor Control Over Winter?

That’s where Happy Campers Holding Tank Treatment shines. Add it with a small amount of fresh water during your final flush before storage. It helps control odor without risking seals or the septic balance at home.

Top 10 Products You Need to Winterize Your RV

We’ve curated the essentials for a smooth, leak-free winter. External links are provided for convenience; choose your preferred retailer.

1) Happy Campers Holding Tank Treatment odor control

Gentle, effective treatment to control odors during long storage without harming seals. Add with a small amount of fresh water after your final tank rinse.

2) RV Antifreeze (Propylene Glycol)

Protects lines, traps, and the toilet seal. Look for potable-system safe, propylene-glycol blends.

3) Blow-Out Plug / Air Adapter

Connects your compressor to the city water inlet for controlled blow-out (30–40 PSI recommended).

4) Water Heater Bypass Kit

Prevents wasting gallons of RV antifreeze in the water heater. Many rigs include one; add if you don’t.

5) Happy Campers Extreme Cleaner spring reset

Industrial-strength, layer-removing cleaner for your spring tank reset. Add with fresh water before your first trip; dump at an approved RV station (not home septic).

6) Freshwater System Sanitizer

For spring startup, sanitize your potable system to remove off-tastes and biofilm before the first trip.

7) Sewer Hose Support / Slope

Ensures a clean, consistent downhill flow during your final dump and rinse.

8) Moisture Absorbers (Desiccants)

Reduce interior humidity and mold risk in storage. Place near soft goods and in closed spaces.

9) Tire Covers

Protect sidewalls from UV damage through winter; rotate or move occasionally to prevent flat spots.

10) Rodent Deterrents

Plug entry points; use repellents near openings. Avoid traps that could sit un-checked for months.

Winter Storage Tips (vs. Winter Living)

Storing Your RV

  • Leave fridge clean and propped open; crack a window slightly if climate allows.
  • Use moisture absorbers and breathable covers; avoid plastic that traps condensation.
  • Battery plan: maintainers or remove and store per manufacturer guidance.
  • Check seals and roof after windstorms; brush off heavy snow loads.

Living/Using in Winter

  • Heated drinking water hose; skirt the RV in extended sub-freezing conditions.
  • Tank heating pads if you keep tanks wet; otherwise operate like boondocking with minimal residency.
  • Ventilate to reduce condensation; run a dehumidifier if you have shore power.
  • Dump less often, with larger volumes to reduce freeze-thaw in the “stinky slinky.”

10 Best Products for Living in Your RV in Winter

These picks help prevent freeze-ups, reduce condensation, and keep you comfortable while living in your RV through the winter (different from the storage/winterizing list).

1) Heated Fresh Water Hose

Prevents freeze-ups at the spigot and along the run; look for NSF-certified hoses with built-in heat cable.

2) RV Skirting (Insulated/Base)

Blocks wind under the rig, reduces propane use, and helps keep tanks/lines warmer.

3) 12V Tank Heating Pads

Adhesive pads for black/gray/fresh tanks; thermostatically controlled to prevent freezing while camping.

4) Pipe/Valve Heat Tape

Self-regulating heat cable for exposed lines and dump valves; pair with insulation wrap.

5) Insulated Vent Cushions

“Pillow” inserts for roof vents to stop heat loss; pop in/out in seconds.

6) Thermal Window Covers

Reflective/insulated covers (e.g., Reflectix) to retain heat and reduce drafts at windows and windshield.

7) Compact Dehumidifier

Actively removes moisture to cut condensation and mold—more effective than passive desiccants alone.

8) Ceramic/Oil-Filled Space Heater

Thermostat + tip-over protection to save propane and reduce furnace cycling when on shore power.

9) Auto-Changeover Propane Regulator

Keeps heat uninterrupted by switching to the full tank automatically—no 2 a.m. freeze surprises.

10) Remote Temp/Humidity Monitor

Phone alerts for inside temps and humidity; catch freezes or condensation spikes early.

Spring Startup Checklist (Tank Reset)

  1. Inspect first: Look for any pink residue (good), obvious leaks (bad), loose clamps, or critter damage.
  2. De-winterize lines: Flush RV antifreeze thoroughly with fresh water at all fixtures (hot and cold). Return water heater from bypass.
  3. Sanitize fresh water system: Run through taps; let sit per directions; flush until clear.
  4. Extreme Cleaner reset: Add Extreme Cleaner with fresh water to black (and optionally gray) tanks. Drive to your first stop to allow sloshing.
  5. Dump at approved RV station: Empty and flush thoroughly. Do not dump into home septic.
  6. Add holding tank treatment: After reset and final rinse, dose with Happy Campers Holding Tank Treatment for ongoing odor control.
  7. Verify sensors: After a few cycles, check sensor readings. If misreads persist, see our sensor guide.
Visual timeline: Fall — Drain, Rinse, Antifreeze, Holding Tank Treatment → Storage → Spring — Extreme Cleaner + Drive → Dump at RV Station → Rinse Thoroughly → Dose with Treatment → Go Camp!

FAQ: Antifreeze, Septic Safety, Sensors & More

Can I use Extreme Cleaner right before winterizing?
No. Extreme Cleaner requires a thorough fresh-water flush and a decent drive to agitate the solution. Once winterized, you can’t do either. Save it for spring startup.
Is Extreme Cleaner safe for home septic systems?
We advise against dumping Extreme into home septic. Septic relies on a delicate bacterial balance; powerful alkaline, grease-cutting cleaners can disrupt that ecosystem if used repeatedly. Use approved RV dump stations or municipal facilities instead.
What if I accidentally dumped Extreme at home once?
An isolated event is unlikely to “kill” a healthy system, but repeated exposure can cause problems. Avoid future dumps to septic and consider a septic health check if you’re concerned.
Do I need holding tank treatment during storage?
Yes — add Happy Campers Holding Tank Treatment with a small amount of water during your final rinse. It helps control odor without risking seals or over-cleaning.
Will Extreme Cleaner damage seals or gaskets?
When used as directed (proper dilution, reasonable dwell time, followed by a full fresh-water flush), it’s compatible with RV tank materials and seals. Always follow label directions.
My sensors still misread after storage — am I broken?
Not necessarily. Sensors are finicky, and residue on tank walls can trigger “false full.” Do a spring Extreme Cleaner reset, flush thoroughly, then run a few normal cycles. If misreads persist, try the steps in our sensor guide.
Is RV antifreeze safe for potable systems?
Use propylene glycol RV antifreeze labeled for potable water systems. Flush thoroughly in spring before drinking from taps.
Blow-out vs. antifreeze — which should I choose?
Blow-out is faster and keeps things tidy; antifreeze provides extra freeze security in deep-cold regions. Many RVers do both for redundancy.
Can I skip winterizing if I store indoors?
If temps can never drop below freezing, risk is low — but many “indoor” spaces still experience cold nights. Winterizing is cheap insurance.

Ready to put your rig to bed the right way?

Winterize now with RV antifreeze and a final dose of Happy Campers Holding Tank Treatment. Then kick off spring with a clean slate using Happy Campers Extreme Cleaner — add before your first drive and dump at an approved RV station.

Next: Save or print the Spring Startup Checklist so you’re ready on day one.