Winterizing Your Camper’s Water System


My sister and her two friends contacted me and asked, “While we are discussing campers. Your sister said you know how to winterize the camper without taking it somewhere and pay for it. What is involved?” So, seeing that I’ve winterized my pop-up and fifth wheel once each, I’m the resident expert in our little circle. Here’s a cleaned-up version of what I sent to them for winterizing their campers.

I’m *way* too cheap to actually pay someone for service. This sounds like a lot, but basically wife and I are able to winterize our big camper in 30-45 minutes. You’ll likely spend as long reading all of this as it does to actually winterize your camper- no matter how big or small! Read each section by clicking the heading below.

Equipment Needed (aka one-time expenses)

You’ll need the following equipment for winterizing your camper. The nice part is a lot of it pulls double-duty with regular maintenance activities.

  • A “RV Blowout Plug” – this screws into your city water connection and lets you push air into the RV lines.
    What I have, a brass blowout plug
    What I have, a brass blowout plug

    What I want, a blowout plug with quick connect
    What I want, a blowout plug with quick connect
  • A small air compressor – preferably one that you can control the air pressure. You generally don’t want more than 30 or 40psi blowing into the system. I spent $100 on one at Home Depot. But you can get a smaller one from Harbor Freight or Sears or something. I wanted a bigger one so that I could also use it for airing up my truck and camper tires. (You are checking tire pressure before each trip and make sure both are inflated to the max- aren’t you?)

    3.5 Gallon Pancake Air Compressor
    3.5 Gallon Pancake Air Compressor
  • A couple of gallons of RV Antifreeze – the pink stuff; not what you put in your car!!! The pink stuff is safe for drinking water lines; the stuff that you put in your car will kill you, seriously. Preferably something that is propylene glycol based (vs. alcohol based).

    RV antifreeze
    RV antifreeze
  • A socket wrench, a 1 1/16″ socket and a 3″ socket extension – for getting the water heater drain off (Note, depending on how this was last put back in, this is either going to be “pretty easy” or “holy craptastic that’s hard”. You might need a “breaker bar“, too.)
    1/2" Socket Wrench
    1/2″ Socket Wrench
    15-piece 1/2" Drive Deep Socket Set
    15-piece 1/2″ Drive Deep Socket Set

    1/2" Drive Extension Set
    1/2″ Drive Extension Set
  • For re-installing the drain for the water heater, using a little bit of plumber’s tape or plumber’s putty will make you much happier next year.
  • You *may* need an anode rod, depending on if you have one and how it looks when you take it out of the water heater. (see this link once you remove it to tell if you’ll need a new one)

Winterization Options

There are a couple of differing views on what you should and shouldn’t do when it comes to winterization. Generally, the colder your climate, the more you should do. (grin)

  • Blowing Out The Lines – some people (me included) like to blow out the lines first and then push the antifreeze in. In some warmer climates, just blowing out the lines. And some folks feel that blowing out the lines before pushing in antifreeze is a waste of time. You makes your choices and you go with what you believe in.
  • Filling Lines with Antifreeze – with blowing out the lines, there is still a concern that low points have some residual water in the that can freeze, expand and cause problems. Without blowing out the lines, the antifreeze pushes out the water in the water lines first and then the antifreeze remains.

Drain Tanks and Water Heater

  1. If your black and gray tanks aren’t empty, they should be emptied.
  2. For this step, the water heater should be off and the water should be cold.
    1. First, find the exterior panel for your water heater and find the pressure relief valve and the drain plug.
    2. Next, bleed pressure off of the water heater using the pressure relief valve to save yourself angst and woe when you remove the drain plug (think shower of water and possible anode rod rocket). This will let water out, so stand clear.
    3. Finally, remove the anode rode. It’ll match in socket from #4 above. Use the socket wrench, socket and extension- remove the drain (which has an anode rod attached). This is a thick rod that gets eaten away as it lives and eventually needs to be replaced. This page has a good chart that shows when an anode rod should be replaced.

    When you remove the anode rod, the water will glug down the side of your camper to the ground. It’s likely about 6 gallons (but can be up to 10 gallons depending on your water heater). Some people will get some paper towels, twist them and push part of into the camper to wick away the remaining water.

    Water Flushing ToolOptional: some people will use a water heater flushing tool to clear out bits of crud from the water heater.

  3. Use plumber’s tape or putty on the threads of the anode rod and re-install it into the camper. It needs to be a touch snug, but you don’t really have to put much pressure on it. In fact, too little pressure is OK. Just in spring- when you go to fill it, remember that it isn’t very snug and just tighten it up if it leaks a little.
  4. Look under your camper for what are called “low point drains”. There are usually 2 of them together. They either have caps on them or maybe have an “on/off” valve that you turn to let water out. You want to open these and let the water drain to the ground. It may help to open/close each water fixture (sink, toilet, shower) to encourage the water to drain out. These drains can be tricky to find sometimes. If you can’t find them, it’s not awful. Let the water out and re-cap/close the lines.
  5. If you use your fresh water tank, it too will have a drain coming out of the bottom of your camper- you want to empty it as much as possible. The drain can be tricky to find sometimes. If you can’t find it, turn on your water pump and just run the outside shower to drain off as much water as possible. Let the water out and re-cap/close the line.

Bypassing the Water Heater

Now, here’s where things get a little tricky as all campers are different.

  1. If your camper has a water heater bypass, you want to bypass it. Sometimes this is as easy as looking in a compartment and there is a clearly labelled switch in your control center where your water hookups are. Other times, you have to look at the back of the water heater and see what kind of valves there are. Or, you might not have one. If you don’t have one, this is likely worthwhile adding (either now, if you’re up for the extra DIY or next year during the season). If you have one, you want the water heater bypassed so that no water goes into it. If you don’t, we’ll just re-empty it at the end.

Blowing Out The Water Lines

This next part is generally a 2 person job, unless you have a locking air chuck. Wife and I will be on our phones to each other:

  1. Start up the air compressor to let it build up pressure. Adjust it so that it regulates the air to between 30 and 40 psi.
  2. Screw in the blowout plug from #1 to your city water connection (aka hose hookup).
  3. Now, in order of faucets, toilets and showers from closes to the water inlet to furtherest:

    1. you want to open the cold faucet.
    2. put the air pressure onto the blowout plug and blow air into the lines. The faucet will push out some water and then will spit and then will be just air.
    3. open the hot, close the cold and wait for it to be just water.

    Don’t forget the toilets! We did and ended up with a leak this spring. For the toilets, you’ll hold the flusher down until air spits out. Remember, you need to do:

    • all faucets
    • all shower heads (including outside shower)
    • all toilets
    • all outside hose hookups that are fed from the onboard water system
    • washer hookup (ok, maybe this is just a reminder for me :-))
  4. If you didn’t find a bypass for the water heater, go ahead and open that drain again and see if water comes out. Maybe do the paper towel trick. (shrugs)
  5. If you have a water filter, open the canister and dump out the water. Throw away the filter (record size/shape/model # if you need to. If you are going to do step #13 below and plan on pumping antifreeze into the lines, you want to fill up this canister with something that takes up space so that you don’t waste a bunch of antifreeze. Capped soda bottles work well for this.
  6. Take some RV antifreeze and pour a couple of cups down each sink (kitchen, bathroom, outside kitchen), shower drains and toilet (just enough to cover the seal on the bottom).

Pushing Antifreeze into the Lines

Blowing out the line is all that I did for the pop-up for one year and the fifth wheel last year. It’s usually sufficient because it doesn’t get grossly cold here (Maryland). However, when you pay to have a camper winterized, they’ll also push pink stuff into all of the lines. I’ll likely do that this year- I just didn’t do it last year because I got confused and then ran out of time. The concern is that while blowing out the lines seems like it gets all of the water out, there may be some residual in low points or dips in the lines.

Note, some people skip the step of blowing out the lines if they’re going to use antifreeze.

  1. Pushing antifreeze into the lines is tricky again because all campers are different. I have a second winterization bypass valve that switches my water pump from pulling water from the fresh water tank to pulling water from an outside hose hookup. I’m able to connect a hose to my freshwater tank fill and have the end of it in a jug of the pink antifreeze stuff and when I run the pump, it’ll actually suck antifreeze from the jug.In other cases, you can use a pump to push the antifreeze in from the city water connection. This is a little more vague to me as I haven’t had to do this. Looks like Camping World has the hand pump and a video (love the guy’s camo).Some people will recommend that you dump a bunch of gallons into your fresh water tank- I really dislike this idea as I feel like this would be hard to undo and get all of the antifreeze out.Final note- in step 6, if you didn’t have a water heater bypass, you’ll likely end up pushing a bunch of antifreeze into the water heater. There are differing opinions on if you want to leave this in your water heater or not over the winter. Personally, I wouldn’t do it. I’d attempt to drain it out.In either case, you want to follow the same basic procedure as blowing out the lines. In order of faucets, toilets and showers from closes to the water inlet to farthest:

    1. you want to open the cold faucet
    2. wait for pink to come out (it’ll likely push some water out ahead of it at first)
    3. close the cold and open the hot water
    4. wait for pink to come out (it’ll likely push some water out ahead of it at first)

    Again, remember all of your water fixtures- sinks, shower heads (inside and out), toilets, washer/dryer hookups and any water hose hookup that feeds from the camper’s water system.

  2. If you use the hand pump, you can also push RV antifreeze into a black tank flush (if you have one). If not, see if there is a water hose hookup on the camper that you might be able to use that to push the antifreeze in for you.
  3. After you fill the lines, you want to back fill your city water connection with antifreeze. To do this, pop off the metal filter screen inside the city water inlet, standing well back and to the side – use a long screw driver press the little button to draw the pink stuff into the line for the city water feed. Note: it will spray pink antifreeze, try like heck to keep it out of your mouth and eyes- it tastes awful. 🙁

Come Spring – Unwinterizing

To unwinterize- you basically just hookup a hose and run water at every tap until just water comes out (same order, nearest to farthest). Many folks will cut the water, dump a little bit of bleach into the end of the hose and then reconnect it to sanitize the lines. Same with the fresh water tank- there are a bunch of ways of sanitizing it, but basically it’s a little bit of bleach into the tank, let it set, drain and flush it out a couple of times.


  1. Plumbers putty, and pipe dope are two different things. When reinstalling you’re hot water heater drain, you want pipe dope! Or Teflon tape . Plumbers putty is used when installing a sink to create a seal if your new Fossett did not come with a rubber gasket.


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