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Can I Just Pour Antifreeze Down My RV Drains?

New RV owners may find pouring antifreeze down their drains concerning, especially if it’s their first time. Most of us know the car formula is highly toxic, but is the product for your rig any different? 

A few cups of bright pink liquid might distinguish between a smooth winter and costly repairs. But how to apply it correctly is up for debate.

We’re exploring best practices for using this fluid to maintain the health of your pipes during the off-season. 

Let’s get scientific!

What Are the Different Types of Antifreeze?

In RVs, the type of antifreeze you’ve seen poured down drains differs from that used in cars. Generally, you add it to your rig’s pipes and tanks because it freezes at much lower temperatures than water. Some formulations remain liquid at 50 degrees below zero.

The product has three main types, each defined by the chemicals included and color. 

Ethanol-based fluids are generally considered safe for use in motor homes. But keep one thing in mind. Over time, it can break down seals and cause them to wear out faster. Because you’ll be using it in your grey and black water tanks to prevent freezing, remember that it’s also likely to kill off good bacteria in waste tanks.

Ethylene glycol is the active ingredient in car antifreeze. It’s usually blue or red and is highly toxic to people and animals. Adding it to your engine will prevent damage during winter. It doesn’t work in your on-board wastewater system because it’s engine coolant. 

Propylene glycol is best for use in your RV’s plumbing system. Most manufacturers produce a pink-hued product. You may see this poured down drains to protect tanks and piping. It’s considered non-toxic, so small amounts in your water won’t kill you.

Regular winter campers may add it throughout the season to prevent damage. However, you’ll take a different approach if storing your rig for the frigid seasons.

This is a popular brand of RV antifreeze: Splash RV/Marine Antifreeze.

A photo of a bottle of antifreeze. Can you pour antifreeze down your RV drain?

Can You Use Regular Automotive Antifreeze in Your RV Drains?

Pouring car antifreeze down your RV’s drains is not a good idea. This product helps engines maintain a steady temperature in the cold. It’s highly toxic; even a small amount can send you to the hospital. Using it in any other application is asking for trouble. 

Most of the time, RVers empty their tanks at campgrounds or home disposal stations. Putting the automotive version in your system means you shouldn’t dump waste at these locations. Many service stations and car dealers can properly dispose of blue antifreeze, but not if it’s mixed in with waste. 

To help with any confusion, some brands now refer to vehicle antifreeze as engine coolant. It’s important to remember the distinction between the products when treating your RV’s water system. Cars use it to keep the engine cool and regulated, not plumbing. 

As with any chemical formula designed for a specific purpose, using it other than as intended could have dire consequences. 

Is RV Antifreeze Toxic?

Propylene glycol, the chemical used in RV antifreeze, is safe to put down your drains. It’s non-toxic, and while we don’t recommend testing this, small amounts are supposedly safe to consume. Essentially, a residual trace left behind after winterizing your rig’s plumbing system shouldn’t make you sick.

A side benefit is that it lubricates the seals of your tanks and keeps them working as intended.

Ethanol is toxic to humans and animals but is safe for RV disposal tanks. As mentioned, beneficial bacteria that break down waste can’t tolerate the chemical. Another drawback is that it erodes seals in the system. 

How to Winterize Your Travel Trailer – Tips for Beginners

Can You Winterize Your RV Without Pouring Antifreeze in the Drains?

Pouring some antifreeze down the drains of your RV is the simplest way to keep it safe during winter use. But a different approach may work better if you put your rig up for the winter. 

Experts recommend first draining the entire system of water by using compressed air. According to Explorer RV Club, some debate exists about how many faucets to leave open. Some folks like to leave them all open, others just one, to allow fluid to run out.

Make sure you’re bypassing the filter before you send air through. Don’t exceed 40 pounds per square inch (PSI) on your equipment to avoid damage.

Once no more water comes through, only trace amounts remain in the pipes. Adding antifreeze at this point for long-term storage protects and maintains vital components. Connect to the inlet and allow the pump to distribute the product through the system. You’ll know the pipes are full when pink fluid flows into your sinks.

Beginner’s Tips: How to Winterize Your Motorhome.

A man filling his water tank using a garden watering can. You'll need to flush your tanks when you're ready to camp again if you pour antifreeze down your RV drains.

How Do You Dispose of Used Antifreeze?

If you only add antifreeze to the drains of your RV, it’s easy to clear out for use. Connect to a water source, allow it to flow, and flush it into your tanks. Because it’s a non-toxic product, you can drain it as you regularly would with grey or black water. 

On the other hand, if you fill the whole system, you’ll want to use water pressure to clear it. Connect through the city inlet and allow it to flow. Remember, a small amount of RV antifreeze in your water won’t harm you. However, if you’ve got time, let it run until you no longer see pink. 

Rather than pouring used antifreeze down the house or storm drain, dispose of it in the same manner as your waste tanks. Even though it’s not toxic, it still isn’t good for the environment.

Different formulas have unique requirements for disposal. Engine coolant is not safe to dump or come in contact with. If you’ve used it in a vehicle, it could contain heavy metals that can harm you and the environment. 

In the event that you need to dispose of dangerous chemicals, take steps to protect yourself. Drain into a large pan and then pour it into a sealable bottle. Use gloves so you don’t touch the fluid. Take the discard to a service or gas station, as most have access to the proper methods. 

Yes, the Pink Antifreeze is Safe for RV Drains!

Unless you know you’ve got the right product, pouring any old antifreeze down the drain in your RV is not a good idea. The correct one is explicitly formulated for motorhome plumbing systems to prevent damage in cold weather. And if you’re a winter camper, it helps avoid damage to your holding tanks. 

Storing your rig outside in sub-freezing temperatures can damage pipes if water is left behind. Using the bright pink stuff provides the necessary protection against the elements.

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