RV Dewinterizing Guide: Sanitizing & Flushing Your System

Tool	Why You Need It
🔧 RV Tank Sanitizer	Bleach ratios for sanitizing
🔧 Best RV Water Pumps	Flush system after antifreeze

RV De-winterizing: Waking Up Your Water System

Spring de-winterization is more than just flushing out pink antifreeze. It is your annual opportunity to verify the structural integrity of your plumbing, sanitize the fresh water tank, and perform critical maintenance on your water heater after months of dormancy.

Field Insight: Do not turn your water heater valves back to "Normal" until after you have flushed the antifreeze out of the main lines. You don't want sediment or residual antifreeze entering the heater tank if you can avoid it.

graph TD Start[Flushing Antifreeze] --> Sanitize[Sanitize Tank & Lines] Sanitize --> Wait[Wait 4-12 Hours] Wait --> Flush[Flush Bleach Smell] Flush --> Heater[Restore Water Heater Valves] Heater --> Leak[Final Leak Inspection]

Step 1: The Initial Flush

If you used the "Pink Stuff" (Propylene Glycol), you must remove it from every branch of the plumbing. Antifreeze is non-toxic, but it has a lingering "slick" texture and a slightly sweet smell that can ruin your first cup of coffee.

City Water Connection: Connect your drinking water hose and pressure regulator.
Fixtures: Open every faucet (hot and cold) until the water runs clear and bubbles stop. Don't forget the outside shower and the toilet flush.
Low Points: Open your low-point drains briefly to ensure no antifreeze is trapped in the "bottom" of the loop.

Step 2: Fresh Tank Sanitation (Bleach Method)

Stagnant water and residual moisture in an empty tank are breeding grounds for bacteria. Sanitation is mandatory after winter storage.

The Bleach Calculation

Use 1/4 cup of unscented, liquid household bleach per 15 gallons of fresh water tank capacity.

Tank Capacity	Bleach Amount
30 Gallons	1/2 Cup
60 Gallons	1 Cup
100 Gallons	1-2/3 Cups

The Scent Test: Once the bleach is in the tank, run the pump and open all faucets until you smell a strong "pool-like" chlorine scent. Shut the faucets and let the mixture sit for at least 4 hours (8–12 hours is better for full sanitization).

Step 3: Restoring the Water Heater

Now that the system is sanitized and flushed, it's time to bring the water heater back online.

Close the Drain: Reinstall the anode rod (Suburban) or the plastic plug (Atwood). Apply fresh Teflon tape to the threads.
Bypass Valves: Turn the two (or three) bypass valves at the back of the heater to the "Normal" position.
Fill the Tank: Turn on a hot water faucet. The pump (or city water) will push air out of the heater tank. You will hear sputtering. Once a steady stream of water flows, the heater tank is full.

Maintenance Tip: This is the best time to inspect your Anode Rod. If more than 75% of the magnesium is gone (exposing the center wire), replace it. See our Heater Component Guide.

Step 4: The Static Pressure Leak Test

Even a small drip can rot an RV floor over time. Perform this professional leak check before your first trip:

Turn OFF city water.
Fill the fresh tank half-way.
Turn ON the 12V water pump until it primes and shuts off.
Wait 30 minutes with no faucets open.
The Result: If the pump "kicks on" briefly during that 30 minutes, you have a slow leak. Check under sinks, the water heater fittings, and the toilet base.

Continuing the maintenance cycle? Check out our Printable Setup Checklist for ongoing trip prep.

Related RV Troubleshooting Guides

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RV Water Systems Troubleshooting Guides

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Adam Hall — Founder, DecisionGrid

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Updated March 2026 · Reviewed for technical accuracy

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Last updated: March 2026 · Reviewed for technical accuracy

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