Winterizing the water system

Now that we’re halfway through winter, I finally found the time to go out and winterize the water system in the Westy. Luckily we rarely dip below freezing up here in the Pacific Northwest, so it hasn’t been an issue – in fact, last year I did nothing other than drain my tanks, and didn’t have any problems.

Others on the sprinter_westfalia list claim that filling the system with antifreeze is overkill, and blowing out the lines with compressed air, then filling the traps with antifreeze is sufficient. That may be, but it also sounds more complicated to me! Especially since hauling my air compressor out of the garage is probably a 20 minute job in itself 🙂

This year I figured I’d be a bit more prudent, and went out and bought 10 gallons of RV antifreeze to take care of all of the tanks, lines, and traps.

At about $5 a gallon, that’s not a bad price to prevent freezing and cracking of lines. But I could have saved a few dollars in antifreeze by installing a water heater bypass kit. They work by bridging the hot and cold water lines immediately before the water heater; instead of the water (or antifreeze) going into the hot water tank and filling it up before it reaches the hot water outlet, the water just skips the tank altogether and goes straight from the inlet to the outlet.

I can never remember how big our tank is – 4 gallons, I think? In which case you can save $20 in antifreeze with an $18 part. Not a huge savings the first year, but next year and each year after you’d save the full $20, and it also keeps some chemicals out of the environment.

Anyway, my process for winterizing was simple:

  1. Drain the gray and black water tanks at a dump station.
  2. Drain the fresh water from the valve outside the van, on the driver’s side. Drain the hot water heater using the valve inside the lower-right cabinet accessed through the van’s rear doors (my valve is yellow).
  3. Pour 8 gallons of antifreeze into the fresh water tank through the exterior fill hole.
  4. Run the bathroom hot water faucet. It took a while for it to change from water to pink antifreeze. Then run the cold at the sink, hot and cold at the kitchen sink, and flush the toilet, until everything’s running pink.
  5. Pour some antifreeze directly into each drain, to fill the traps. Don’t forget the shower drain in the floor.
  6. I poured an extra gallon down the toilet to make sure there was enough in the black water tank.

Total time: 20 minutes
Total cost: $50 (10 gallons of RV antifreeze)

In the spring I’ll have to rinse it really well, since I don’t like the idea of antifreeze in my water system. But I like the idea of burst pipes even less 🙂

How do you winterize your system? Have you installed a water heater bypass that worked well (or that didn’t work well!)?

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5 Responses to Winterizing the water system

  1. Ted says:

    Nice writeup, Mike.

    The use of RV antifreeze in the fresh water system isn’t really necessary, but it can’t hurt. My winterize procedure goes like this:

    – Switch water pump off via toggle switch in dish cabinet
    – Place bathroom faucet in shower holder; open it and kitchen faucet to midway between hot and cold
    – Open water fill valve; drain fresh water as described above
    – Open yellow toggle at base of water heater as described above. I also check the anode rod and replace with teflon tape.
    – Depress toilet pedal and hold for a few seconds
    – If van is not 100% level, open city water connection and push plastic check valve with finger to release any water there. (This froze one year when the van was leaning toward the rear)
    – Close all openings except for faucets
    – Drain holding tanks at dump station.
    – Freeze-proof the traps, as described.

    With this method you can get away with just a quart or so of antifreeze. It takes only 10 minutes.

    Best regards,


    • mike says:

      Nice – thanks Ted! I hadn’t thought about the city water connection, that’s a good tip. I’ll go press on the check valve this evening.

  2. ST says:

    Lessons Learned:
    As a new owner of this awesome rig I should have been extra careful draining the water system before the Alaskan winter arrived. Always had the old slide-in truck camper properly put away…but these units need more attention to detail. Basically, I failed to drain every line, including the water heater. EVERYTHING in the system had to be replaced. Total cost including labor was just under $4,000.00
    Insurance DID NOT pay for one penny of the damage. Tough lesson – wish the money could have been spent on a road trip!

    • mike says:

      Oh no!! That’s terrible luck – sorry to hear it, ST.

      Did they use all original parts? Did water tanks need to be replaced? At $4k it sounds like your water system *exploded*!!

      I hope it’s the last thing you have to replace on the van.

      • ST says:

        The new replacement parts were all MADE IN USA and saved a bundle of money plus waiting time I might have experienced if I’d insisted on original German parts. The USA materials are used in all the new Sprinter-based RV’s and easier to get spare parts for.

        It is always a good idea to replace old water lines on a periodic basis, as algae/mildew/mineral deposits may build up in the typical water supply lines of older campers despite using RV antifreeze in the tanks. Mine just cost a wee bit more…..

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