How to Fix Frozen Bathtub Drain

Frosted bathtub drains are inevitable if you live near freezing temperatures, such as those found in northern areas. This can be explained by freezing weather as well as inefficient piping and wall leaks that lead to cold air entering the trappipe and freezing it.

If a boiling kettle fails to disappoint you and your beloved plunger plunged away without success, and water remains in the tub, you are left with no idea how to melt it or flush the accumulated water down the drain.

Resolution # 1

The Wet/Dry DryVac + Blow Dryer Method

If you find a wall that is open at the drain end of your tub, break it or cut it. After drying the pipes, blow-dry them to remove any frozen pipes. Insulate the area to keep it from freezing again. Mount the access panel doors in the area of the cut.

If that fails to work, move on to the next step.

Take a wet/dry vaccuum and extract any remaining water. Next, use hot water to unclog the tub’s frozen drain. You could try sucking the water out of the tub and using the blow dryer on high to dry it. I’ve seen salt being used for thawing. But, if you have pipes made from metal (especially the trap), there is the possibility of the pipe becoming contaminated and you may end up with more problems. Good luck! Please leave feedback below about your experiences with the bathtub drain thawing method.

Remedy #2

Baking Soda + Vinegar Method

Sprinkle a handful baking soda in the tub drain. Let it sit for 60 second. You will now need to pour 1 cup distilled white vinegar into your drain. Let it sit for a while for the chemical reaction. As a result of the chemical reactions taking place in your vessel, you’ll notice bubbles appearing and a fizzling sound. The mixture will remove sludge and clear out frozen blockages. If the baking soda and vinegar mixture are already in the drain continue to step 2.

Mix 3-4 cups water with salt. Slowly transfer to the drain of your tub. This will allow for the baking soda/vinegar mixture to percolate into the frozen plumbing. Salt is a strong ingredient that accelerates the melting process of ice.

After clearing the clog, run hot water down the drain until the pipes are fully thawed.

Resolution # 3

Space Heater

A space heater or heatlamp can be used to warm the area. Hot water with safety salt can also be poured down the drain. It will melt the frozen bathtub drain. To avoid a potential fire hazard, place the heater 8 inches away the tubing or walls. Be sure to keep any flame-catching rugs, carpets or other items away from the heater.

Mix and Match Other Items To Create A Stronger Impact…

You can combine any combination of the remedies above with these methods to achieve a more powerful thawing result.

Warming Pipe

Find the frozen part of your sewage pipe. Search for the coldest area of the tubing with your fingers. If you’re unable to locate an origin, move on to the tube closest.

Use a hairdryer. From the coldest area, heat the tube. Wrap hot towels in place of the frozen pipe to keep it from getting damp. You can thaw the pipes until all water has returned to the pipe.

Warning: Never try to heat the pipes by using an open flame.

Vent Pipe

You could even consider heating the vent pipe (also known by a vente stack). Also called a vent pile. This is the conduit from which the outside air leaves the house. This is the conduit that provides fresh air to your plumbing equipment. It can remove odorous particles from your home.

To drain the water, the ventilation tube has to filter fresh air through the drainage channel. The vent tube cannot function if it has frozen and will block the drain.

If you are handy and not afraid about heights, enter your attic. Check to see if it is frozen. Use the hairdryer to heat it up.

Higher Heat Levels

People will reduce heat in an attempt to save money. The result? Frozen pipes. The heat should be turned up to a higher setting than what you have used. I am not suggesting that you heat your home to unbearable levels. This is just the normal heating level. You can open your doors to let the heat reach those places that have not been heated.

This Guide is for plumbers only: How to prevent future freezing in the bathtub drain

If you live in colder regions, freezing your bathtub drains can be a problem.

Locate any leakage or inefficient insulation and open up the area. The wind is a major cause of frozen pipes. Even a slight opening in the area will allow enough cool to freeze the drainage pipes. I will remove any insulation that is not required for visual examination. In such cases, an ultraviolet camera is useful. A common misconception is that fiberglass insulation won’t stop air infiltration.

I met a customer that was having the same issue. Air leaked through insulation, through the vent in the soffit into the wall area and allowed the bathtub drainage pipe to freeze.

Proper vents are essential to ensure the proper airflow, from the eaves up to the Ridge vent. They are made of Styrofoam. Then insulation is added. Vents that allow fresh air to flow up the roof’s underside via the soffit and roof vents are properly designed. The soffit vente allows air to flow into the appropriate vents in the attic. This keeps the attic cool and helps moisture evaporate. A good ventilation system can help prolong the life span of shingles as well as prevent ice damming.

Insulation that’s too tightly packed is another problem that I have encountered. Fiberglass insulation must be loose and fluffy. Compacted fiberglass will lose its Rvalue if there is a limited amount of dead air space. Fiberglass insulation doesn’t need to deteriorate when it’s installed correctly.

To solve my problem I attached Styrofoam vents above the soffit. I then installed fiberglass high-density insulation. If you have the funds, “Open-cell spray insulation” is a good option. It is essential to ensure that the insulation batts are securely in place. The edges need to be secured by placing folds. These folds may be rolled up and piled onto the wood board.

The floor floor rim joists or the portion of exterior wall on the floor joint should all be tested and insulated. The electrical connection and dryer vents should also be checked. Finally, piping should also be checked for air leaks.

After insulation, I filled all areas with 1.5-inch Styrofoam rigidboard insulation. This sealed air gaps and increased the R value. To seal any gaps in the board, I used foil HVAC Tape. For some larger holes, I sealed them with expanding foam. This not just warms your unheated space, but also prevents any air from flooding your bathtub drainage pipes and traps.


A well-conditioned drainpipe drains normally dry and doesn’t freeze during usage. However, drainpipes can freeze in below-zero temperatures. A blocked drain is likely to freeze as it holds water. A drain that is not properly pitched will freeze the water. A dripping tap will cause water in the drain to freeze and cool several meters further down. This is one reason why I shudder whenever I hear people suggest keeping a faucet dripping in order to prevent pipes freezing. In my ten years of plumbing experience, I have come across many cases in which the primary main sewage pipe became frozen because of a leaky faucet or a leaking bathroom.

If you have not experienced either of these freezing situations, your only point of drainage is the trap underneath the tub drain. The trap is an oval-shaped drainage tube with water that prevents sewage from entering the home. Heating it will open the frozen tub drain. This trap can be reached either through the ceiling or wall behind the tub drain. Let the water flow from your hairdryer reach the trap area and watch the ice melt away. If that fails, you can check for pipe problems and use the remedies I provided earlier. But in most situations this should work.

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