As we write this in late fall, many RVers are thinking about winterizing their RVs. Depending on where you live, the question “How long does it take for water to freeze in RV pipes?” becomes more important to answer with every passing day.
As the temperature drops everywhere, we think it’s a good time to take a look at how the cold weather can affect your RV’s plumbing.
Frozen pipes present issues we all want to avoid, but what is the freezing point of the water in your RV water lines? How long does it take for RV pipes to freeze?
In an effort to avoid finding out the hard way, we’re investigating that question today.
How Long Does It Take for Water to Freeze?
We can answer this question generically, but we’ll need to consider several variables when we relate the question to RV plumbing.
Regardless of other variables, the freezing point of water is 32 degrees Fahrenheit (or 0 degrees Celsius). That much is standard information. 32 degrees F (0 degrees C) is when water molecules slow down enough to connect to each other and start forming solid crystals.
But we need to take some more specific information into account when we’re relating the question to our RVs.
The amount of time required for water to freeze in certain situations depends on other factors such as how much water is involved. So, surface area matters.
For example, it generally takes 3 to 4 hours to freeze water in standard-sized ice cube trays. But there are some smaller ice cube trays in which the volume of water you’re freezing for each cube is significantly less than that used in a standard ice cube tray. The water in those tiny ice cube trays will freeze in only an hour or two.
Similarly, freezing a bottle of water in your home freezer will require more time than a small tray of cubes. And here again, the size of the bottle will be a factor: if you’re freezing the water inside a standard 12 oz plastic bottle, less time will be required than if you’re looking to freeze a one-liter bottle of water.
So, volume matters.
The shape and size of the container in which the water is freezing also make a difference.
And even the freezer itself is a factor.
So, while we know that the freezing temperature of water is 32°F (0° C), we’ve got other variables to consider when we’re thinking about our RV plumbing and tanks.
That’s why the title of this post is, “How Long Does It Take for Water to Freeze in RV Pipes?”
Let’s check it out!
How Long Does It Take for Water to Freeze in RV Pipes?
Anytime water lines are exposed to freezing temperatures, it’s possible for pipes to freeze. But RV pipes are even more vulnerable because the areas around them are often poorly insulated because RV manufacturers generally operate on the common assumption that most rigs are used during the warmer months.
Water has the unique property that it expands when it freezes and your RV’s plumbing system can handle only so much expansion. Water lines, plastic fittings, valves, and water pump parts can crack when water in the pipes freezes.
As for how long it takes for freezing to occur, there will be several variables to consider.
Not all RVs are the same. Some RVs have more insulation than others, so some are able to handle freezing temperatures longer. Some RVs have plumbing contained in insulated or even heated spaces where the water lines are better protected.
For example, you may have seen our post on the so-called “4-season RV“. Some of these RVs could be in temperatures below freezing for 24+ hours and the rig’s plumbing wouldn’t freeze.
However, without specific protection and in certain conditions, RV pipes can literally freeze within a few hours depending on how low temperatures drop. If they plummet below freezing, your RV plumbing is likely at risk if it isn’t properly winterized.
If temperatures are basically hovering at around freezing or slightly below, your RV pipes are likely to freeze in roughly 24 hours.
But, other variables do come into play. For example, if you’re actively using your RV and you’ve got the furnace or a space heater running, this will factor into the situation. If your RV is parked outdoors unused for the “off-season” and temperatures fall below freezing, your pipes and other plumbing fixtures are more likely to freeze and be damaged.
Temperature is a factor as well. If your rig is parked in an area where temps drop into the teens, it won’t take long at all (as little as a few hours) for unprotected RV pipes to freeze.
This is why it’s so important to winterize your RV properly. For more information, check out our post on RV winterizing tips to help you to avoid common winterizing mistakes. You may also want to have a look at our post on blowing out RV water lines vs antifreeze.
We’ve also got a post on how to winterize an RV with an air compressor.
Note that you’ll still need a gallon or two (depending on the size of your rig) of RV antifreeze for this process. You’ll want the antifreeze specifically designed for potable water systems. (See our post entitled, “Is RV Antifreeze Toxic?” for reference.)
Prefer a visual tutorial? Here you go!
Can RV Pipes Freeze in One Night?
Yes, they can. If outside temperatures drop well below freezing, it’s possible for your RV’s pipes to freeze overnight. In fact, if temperatures fall into the teens or even lower, your RV pipes could freeze in mere hours.
This is why RV owners who anticipate their rigs being in locations where temperatures can plummet into the teens and even into the single digits start thinking about winterizing their rigs in late fall.
Will RV Holding Tanks Freeze?
Going back to the earlier discussion about the time-to-freeze depending in part on the amount of water freezing, RV tanks can hold a lot of water. And the more water there is in a tank, the longer it will take to freeze.
As with RV plumbing in general, there are a number of variables to consider when discussing the freezing point of an RV holding tank.
If you’re RVing and you’ve got water in your tanks, as long as temperatures rise above freezing during the day, an overnight freeze is unlikely to freeze your holding tanks.
As to the question of how long it takes for an RV holding tank to freeze, that’ll depend on the length of time it’s exposed to freezing or sub-freezing temps, as well as the design of your specific RV.
For example, if your rig has an enclosed heated basement, it’s going to take a lot longer for your tanks to freeze than it will for a rig with exposed tanks.
You may have seen our post on RV tank heating pads. In it, we note that while some rigs come with insulated holding tanks, many do not. If desired, holding tank heating pads can be added.
Keeping your RV fresh water tank full will also help to avoid freezing, as will using heat tape on your RV’s pipes and/or tanks.
You can see our posta on heat tape for RV water hoses, and you can purchase various lengths of heat tape as well as heavy-duty extension cords on Amazon.
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Or, if you’d rather not make your own heated water hose, you can buy them pre-made: Best Heated RV Water Hose Options.
We use the best one on the market — NoFreezeWaterHose. You can get a discount on one for your own rig with the link and discount code here:
Can My RV Water Heater Freeze?
It can, and a freeze could even destroy your water heater’s tank. However, if you’re using your water heater regularly, and your water heater is on, the temperature of the water will stay above freezing and your hot water tank won’t freeze.
With that said, if your RV isn’t being used – or the water heater isn’t being actively used – it really needs to be drained. In fact, this is a very important part of the winterizing process.
To learn how to drain your RV’s water heater, please see our post on how to do an RV water heater flush and inspection where you’ll also find a video to follow along with if you wish.
How Do You Keep RV Pipes From Freezing?
The very best way to keep your RV pipes from freezing is to winterize your RV properly before your rig gets exposed to freezing temperatures.
If you’re using your RV in freezing or below-freezing temps, you can attempt to keep your pipes from freezing by insulating or heating your storage tanks and your water hose as noted above, and by only dumping your tanks when they get full.
You can also open any cabinets that house interior plumbing (to allow warm air to cirulate around them), use a space heater in your rig to keep it warm, and use RV skirting for winter if your rig is stationary for a long duration of time.
One last time (just for good measure) we strongly advise winterizing your RV ahead of when temperatures are expected to plummet!
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