How To Fix A Frozen Bath Tub Drain? The Best DIY Tub Drain Thawing Remedies

If you live in the cold areas, where you get freezing temperatures for many weeks a year – you definitely have to encounter frozen bathtub drains. The explanation behind this is not only freezing weather but also inefficient piping and leaks in the wall that contribute to cold air entering the trap pipe and freezing it.

If a boiling water kettle disappointed you, your beloved plunger plunged away to no avail, and you still have water standing in the tub and you are absolutely utterly confused on how to melt the ice block and flush the accumulated water in the drain — here I have listed my PROVEN DIY techniques to thaw a frozen bathtub drain without calling the plumber.


Remedy # 1

The Wet/Dry Vac + Blow Dryer Method

If there’s a wall (closet) that can be opened at the drain end of the tub, you can break/cut the access panel at the floor level and blow-dry to thaw the frozen pipes. Then cover it up with insulation for future help. Purchase an access panel door to mount in the place of the cut.

If that fails, continue to this next step:

Take a wet/dry vacuum, extract the existing water, and use more hot water until the bath tub’s frozen drain is unclogged. Or you might suck the water and target the blow dryer on a hot setting inside the tub drain. I’ve seen people use salt for thawing, but if you’ve got metal pipes (especially the trap), you’ll risk the chance to eat it and cause more trouble. Good luck and let me know about your experiences with this bathtub drain thawing remedy in the comments section below.

Remedy # 2

Baking Soda + Vinegar Method

Pour a handful of baking soda inside the tub drain, and wait for 60 seconds. Now pour 1 cup of distilled white vinegar into the drain and wait for a few minutes for the chemical reaction to take place. As a consequence of the chemical reaction taking place in the vessel, you will notice bubbles and fizzing sound. Apart from clearing the frozen block obstruction, the mixture will also cleanse the pipe, removing sludge. While the baking soda + vinegar mixture is already in the drain, continue to step 2.

Mix salt in 3-4 cups of boiling water. Slowly transfer the mixture to the tub’s drain. This will enable the percolation of the baking soda and vinegar mixture inside the frozen piping. Salt is a really strong element that accelerates the ice melting process.

As soon as the clog is clear, run good amounts of clear hot water down the drain to ensure the drainage pipes are properly thawed.

Remedy # 3

Space Heater Method

Use a space heater or heat lamp to really warm up the area and also pour hot water mixed with safety salt down the drain. It will thaw the frozen bathtub drain. Hold the heater 8 inches away from the tubing or the walls to prevent a fire hazard. And make sure there are no flame-catching rugs or carpets in front of it.

Combine Some Additional Things For A More Powerful Effect…

You can combine any of the aforementioned remedies with these below-listed techniques for a more powerful thawing effect.

Warming the Pipe

Locate the frozen part of the sewage pipe. With your fingertips, search for the coldest part of the tubing. If you cannot identify an origin, start working on the tube nearest to the tub drain.

Use a hairdryer. Start to heat up the tube from the coldest portion. If the region outside the frozen pipe is damp, wrap hot towels all over the pipe. Thaw the piping until the complete flow of water is restored.

Warning: Never attempt to warm the pipes using an open flame.

Warming the Vent Pipe

You may even consider heating the ventilation pipe (also called a vent stack). (also called a vent stack). This is the conduit that exits out of the house. It is meant to provide fresh air for your plumbing equipment. It expels odorous air from your home.

To drain the water, the ventilation pipe has to filter fresh air into the drainage channel. That being said, if the vent tube is frozen, it cannot function and the drain will be trapped.

If you are handy (and not frightened of heights), enter into your attic and see if the exhaust pipe is frozen. You should use the hairdryer trick to warm it up.

Increase The Heat Levels

In order to conserve money, people often reduce the heat and it comes back to haunt them in the form of freezing pipes. Switch the heat up to a higher degree than you’ve been using. Nor am I speaking intolerably hot but just a regular degree of heating that is not a money-saving level. Open up so that the heat reaches unheated places.

Preventing Future Freezing of BathTub Drain: Here’s What I Did & So Should You As Well (A Guide Exclusively for Plumbers)

Bathtub drain freezing is a major problem (when you live in cold regions, obviously) and also when pipes run across exterior walls and uninsulated or poorly-insulated attics.

Open the area to search for uninsulated places and leakage of air. The wind is a significant contributor to frozen pipes, and even a slight opening will allow enough cool air to freeze the drainage pipes. For a good visual examination, I will strip all the old insulation. An infrared camera is helpful in such cases. One thing people don’t know is that fiberglass insulation doesn’t block air infiltration; air leaks must be prevented for it to function.

I came across a customer, facing a similar issue. Air leaked through insulation and through the soffit vent into the insulated wall area, allowing the bathtub drainage pipes to freeze in that wall area.

Proper vents guarantee the proper amount of airflow from the eaves to the ridge vent. Typically, they are constructed of Styrofoam and come in numerous shapes and sizes. After that, insulation is placed over them. Proper vents are built to help fresh air to flow up the underside of the roof via the soffit vent and out of the roof vent. A soffit vent helps air to pass into the appropriate vent in the attic. This tends to keep the attic cool throughout the summer and encourages moisture to evaporate. Appropriate ventilation also helps to extend shingle life and avoid ice jams.

Insulation jammed into spaces is another issue that I sometimes encounter. Fiberglass insulation must remain fluffy and relaxed. Provided that its dead-air space is limited, compressed fiberglass ends up losing its R-value. If correctly installed, fiberglass insulation won’t deteriorate.

I attached Styrofoam vents to the soffit vent to fix my dilemma. And I reinstalled fiberglass high-density insulation. “Open-cell spray foam” is also a better option (if you can afford it). It is necessary to secure the insulation batts in place. This is why the folds are placed around the edges. These folds may be opened and piled onto the wooden board.

The floor rim joist or the portion of the exterior wall of the floor joist should be tested and insulated; the electrical connection, dryer vents, and piping should be examined for air leaks, and foam insulation or caulk should be used to keep the hot air in and hold cold air out.

After insulating all of these areas, I filled the whole outer wall and rim-joint areas with 1.5-inch Styrofoam rigid-board insulation to shut air gaps and maximize the R-value. I also utilized the foil HVAC tape to seal all board gaps, sealing some wide holes with expanding foam. This not only warms your unheated wall space but also prevents the flood of air that freezes your bathtub drainage pipes and traps.


A well-conditioned drain pipe typically drains dry and doesn’t freeze during use. However, it is common for a drainpipe to freeze in sub-zero temperatures. A blocked drain will freeze since it holds water in the pipe. A drain not correctly pitched will retain water and freeze it. A dripping faucet will cause water to cool down and freeze several meters down the drain line. This is one of the aspects that make me shudder anytime I hear people recommend keeping a faucet dripping to avoid the pipes freezing. In my 10 years of plumbing job, I have come across several cases where the primary sewage pipe got frozen by a leaking toilet or a faucet.

If you haven’t had either of the above freezing situations, the only spot your drainage line is frozen is the trap under the tub drain. The trap is a T-shaped drainage tube containing water that stops sewage gasses from entering the house. Heating it will unclog the frozen bathtub drain. Gain entry to this trap either through the wall of the room at the back of the tub drain or through the roof below. Guide the flow from the hairdryer to the spot where the trap is, and see the ice melt away. If this does not work, you must check for pipe flaws and try the remedies I described earlier, but in most situations, this should work.

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