How Much RV Antifreeze to Put in Holding Tanks?

Winter brings a lot of soothing memories and amazing adventure opportunities for everyone but it’s not all bells and whistles for RV owners. Unlike normal vehicles, RVs are like a house on wheels that need identical maintenance and care for a perfect outdoorsy experience.

With low temperatures come high responsibility, and winterizing your RV is the epicenter of that. You should use quality antifreeze to keep the water from freezing in the holding tanks and bursting the plumbing on your RV.

How much RV Antifreeze to put in holding tanks? Which antifreeze is best for your RV? And why is it so important? We have answered all the buzzing questions in detail in this comprehensive guide, so keep reading and take an informed decision.

Which RV Antifreeze Should I Get?

There are different types of Antifreeze available for RVs and motorhomes that are marketed with different names and qualities. When choosing an Antifreeze for your RV, your focus should be mainly on the composition.

The two most common types of Antifreeze you’d come across would either be alcohol or propylene glycol-based.

Alcohol antifreeze is more toxic in comparison to propylene glycol and is used by most R owners, especially for storage in the fierce winter season. Propylene glycol-based antifreeze is less toxic and corrosive, and apart from being more versatile, it acts as a lubricant as well.

Nowadays, a blend of antifreeze is gaining momentum due to its better temperature control and least corrosive nature. You should also get BLEND RV antifreeze to optimally winterize your RV.

How Much Antifreeze to Put in RV Holding Tanks?

On average, you should ideally put 2-3 gallons of antifreeze per holding tank in your RV. But the exact amount of required antifreeze is defined by different factors. These include the size of the RV, the capacity of the holding tanks, anticipated temperatures, and the type of RV antifreeze being used.

Anyhow, you should remember the rule of thumb when it comes to adding antifreeze to your RV’s holding tanks. The majority of RV owners and fan clubs agree on this rule, which defines the amount of antifreeze based on the size of the RV.

For smaller RVs that measure 18 feet in length or less, the holding tanks are equally smaller as well. So you’d be fine with just 2 gallons of antifreeze per holding tank, depending on the climate and length of your outdoor stay.

Medium-sized RVs that are no longer than 28 feet usually require 3-4 gallons of antifreeze per holding tank. Whereas, for large-sized RVs measuring beyond 29 feet in length, 4-5 gallons of RV antifreeze would suffice.

Always pack extra RV antifreeze when setting out on your offroading journey as the temperature could get very chilly out there and you don’t want your plumbing to burst in the middle of nowhere.

Why is Antifreeze So Important for RVs?

Antifreeze is a substance that prevents the water in your RV’s tanks and pipes from freezing, as the name pretty much implies. Before leaving on a winter camping trip or parking your RV for long, you should add good quality antifreeze in a substantial amount.

Antifreeze ensures that water and other fluids in your RV’s holding tanks and plumbing don’t freeze, which might cause the RV’s plumbing to leak, or even explode. Moreover, not using any antifreeze at all could harm your RV’s pricey water heating system and valves. 

Additionally, it stops the accumulation of corrosive substances like rust and other elements that could damage your RV in the longer run. The pain of repairs and rebuilds is avoided, and your RV is kept ready for the exciting upcoming season.

Should I Use Antifreeze in Freshwater Holding Tank?

The water pipes and plumbing in your RV begin in the freshwater tank, so if the water freezes in there, it might have disastrous effects on your motorhome. So, it is crucial that you definitely use antifreeze in your RV’s freshwater tank.

To prepare your RV for the winter, add RV antifreeze to the freshwater tank. Turn on the pump after that, and let the antifreeze drip from each outlet in your RV. This will ensure that the water systems in your RV are completely coated with antifreeze and won’t harm them while it’s parked.

This will ensure that the water systems in your RV are completely coated with antifreeze and won’t harm them while it’s parked. When using the RV, don’t forget to drain and flush the system because these fluids can become poisonous and hazardous for ingestion after standing for a long period.

How to Drain an RV’s Plumbing System?

Follow these steps to safely drain your RV’s plumbing, using an air compressor.

  • An air compressor and blow-out plug are the first set of equipment that you need.
  • Shut all the systems (turn everything off) and disconnect the outdoor water source in the RV.
  • To drain all water, turn on the taps and the system drain valves.
  • Flush the toilet and other water outlets.
  • The “blow-out plug” should now be connected to a water inlet (not the freshwater tank).
  • Set the pressure to 30 psi or lower pressure on the air compressor to prevent damage. (Never operate the air compressor at a pressure higher than 30 PSI).
  • At this stage, drain your RV by connecting the air compressor’s hose to the blow-out plug.
  • Only close the drain valves after the holding tanks have been entirely emptied.
  • Now, add the necessary amount of RV antifreeze to the holding tanks. Alternatively, you can pump the antifreeze into the pipes directly as well.

Alternatives to Using Antifreeze

If you cannot find RV antifreeze or want to rely on other conventional methods of winterizing your RV, these are some of the common and easy ideas that you could use;

  • RV Tanks Heating The freshwater, greywater, and blackwater holding tanks of an RV are equipped with an electric heating system on the underside. The RV’s electrical system is hooked to the heating pads or rods. This setup keeps water from freezing and is a viable alternative to antifreeze.
  • Skirting RV skirting is a technique for insulating your RV’s plumbing that involves covering the chassis and underside with large sheets to trap the heat inside. RV skirting is a wonderful alternative for winterizing if your RV will be stationary for the whole winter. This isn’t a practical option for travelers on the go all winter because RV skirting may be bulky, heavy, and difficult to move.
  • Heated Hoses Heated hoses connect to your RV’s electrical system similarly to heating pads for the tanks. Hoses can aid with winter tank emptying but are not of much use if your tanks or other plumbing components freeze during the drastic temperature fall.

Final Word

RV antifreeze is an essential part of winterizing your RV. Applying the right RV antifreeze solution and properly winterizing your RV by following the instructions are crucial. You’ll normally need 2 to 5 gallons of antifreeze treatment to properly winterize an RV, and if you intend to spend the winter in your motorhome, pack enough of it while traveling and must consider other smart alternatives for keeping the holding tanks from freezing, if required.

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Philippe strives to give you the best overview of automotive equipment, tools, parts, and solutions to a variety of complex automotive problems, based on his own experience. You can read his car reviews on TopSpeed.

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