how to blow out rv water lines

How To Blow Out RV Water Lines For Winterization

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When the camping season ends, and before the temperature drops, you’d want your RV to get ready for winter. You can take your motorhome to a local RV maintenance and repair shop to winterize your rig. However, if you’re a DIY RVer, you can do this vital task without paying for a maintenance fee.

Your RV’s plumbing system requires some preventive measures. You’d want to winterize your motorhome, so you don’t have to pay expensive repair bills because of the damaging result of the winter. This post will walk you through on how to blow out RV water lines to prep your rig for winterization.

Before we go to the ‘how’ part, we’ve listed the things you need and why you’d want to blow out your RV’s water lines. So, continue reading and find out the most effective way to blow out the water lines of your RV.

Blowout Plugs

Blowout plugs are usually plastic plug that easily connects into your RV’s water inlet to help you remove excess water. These caps are made of durable plastic, but there are also stainless steel rustproof plugs that prevent it from corroding and freezing.

The blowout plugs connect your RVs exterior water intake to an air compressor. When a powerful air flows through the waterlines, drains, and faucets, it prevents your water lines from damages and cracking. It’s easy to use and offers a cost-effective solution to help to winterize your motorhome.

Blowout plugs provide an easy way to clear out leftover water in your RV’s city water lines. The aid of blowing out water lines help RVers to save money on antifreeze and protects the rig so it will be ready for the next camping season.

Why you need to blow out water lines

Even little water left in valves, faucets, and pipes can freeze and expand your RV’s waterline, and eventually, it will split apart. Repairing your motorhome can be expensive since most waterlines hide inside the walls and cabinets of an RV

It’s vital to winterize any motorhome or camping trailer that has running water capabilities. Because if you don’t, the water tank and pipes could expand and burst that can cause extensive damage to your RV.

It’s best to keep your rig safe and protected from such weather conditions. You can keep your RV under a shelter with favored humidity, or a fabric cover made for an RV.

We know that winterizing an RV tends much work, but it’s worth the effort knowing that you get your RV ready for your next camping trip.

How To Blow Out RV Water Lines for Winterization

Follow these steps to blow out your RV’s water lines.

  1. You should remove any inline water filters and bypass
  2. Drain the freshwater tank, including gray and black holding tanks.
  3. Remove the water from the water heater and waterlines.
  4. Open the hot and cold faucets to drain water.
  5. Place the blowout plug to your water intake valve.
  6. Using an air compressor, connect the other end of the blowout plug.
  7. Set the air pressure to 30 psi up to 40 psi to avoid water line damages.
  8. Use the air compressor to blow strong air into the lines.
  9. Open up your water valves one a time to blow out excess water from the lines.
  10. Remember to close the valve after blowing the water out from each line.
  11. Blow out all the water lines by repeating the process 10 and 11.
  12. After you have finished blowing out all the water lines, you can now apply the antifreeze.
  13. Add the RV antifreeze to each drain and toilet tank.
  14. You can install a bypass line to your water heater to limit the amount of antifreeze going through the water lines. Most water heaters use six gallons of water.
  15. Turn on the RV water pump to pull the antifreeze out from the jug into the waterline system.
  16. Open each valve to allow the flow of antifreeze water, until it’s finished.
  17. Pour in detergent into the gray and black water tank.
  18. Pour ten gallons of water to both gray and black water tanks.
  19. Close the toilet flush and pour a little antifreeze into the bowl.
  20. Once you have done all this, pour a little RV antifreeze to each drain to protect the trap. 

After closing the blowout plug and removing from the air compressor, you can now park your RV in a safe shelter. 

Things you need to blowout the RV waterlines

Before you start to winterize your RV’s waterlines, there are a few things you need first.

  1. Three gallons of non-toxic RV antifreeze, depending on the size of your RV, you can opt to six gallons.
  2. Temporary water heater bypass jug and kit
  3. An air compressor
  4. Blow out plug
  5. You will need tubing or a water pump converter kit to connect the inlet side of the water pump
  6. Hand tools to remove drain plugs
  7. A wand to clean out holding tanks

Note: Most RVers prefer to have a ten-gallon air compressor to make sure that no water is left after winterizing an RV. Always remember to keep your air compressor not more than 30psi to 40psi.


Keep in mind to winterize your RV's water line to prevent further damage to your motorhome. This way, you are protecting your mobile home investment, plus it also keeps your RV durable and ready for the next season camping.

Now that you understand how to blow out RV water lines, you can share these tips with your fellow RVers.

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