How to Unfreeze a Frozen Drain Pipe? – WarmZilla Answers
Key Takeaways
- Climate change is here, and the UK will experience more frequent cold snaps, potentially causing pipes to freeze.
- Slow drainage, unusual noises (gurgling or bubbling), foul odours, and visible frost or ice on the pipes are clear indicators that your drains are frozen.
- There are safe methods to unfreeze your drains.
- Prevention is best.
As temperatures outside start to drop around the UK, many will want to start preparing their homes for the big chill of winter. In a previous post, we discussed unfreezing frozen water pipes. Now, we’re focusing on drain pipes.
But why should anyone in the UK learn how to unfreeze drainage pipes?
Why You Need To Know How To Unfreeze Drainage Pipes
You might wonder why anyone in the UK would need to know this. The simple answer is Climate change is happening. With climate change upon us, there will be more frequent and extreme weather events due to the slowing down of the Atlantic Meridional Overturning Circulation (AMOC).
According to a quote by Professor Peter Ditlevsen of the University of Copenhagen about the risks of AMOC collapsing, if the AMOC is to collapse, the UK will be a much colder place in the future,
“If Britain and Ireland become like northern Norway, (that) has tremendous consequences. Our finding is that this is not a low probability,”
While being environmentally conscious is essential (and helps reduce heating costs), learning to unfreeze a frozen drain pipe could be helpful in these changing conditions.
Now, what are the signs that you have a frozen drain pipe?
Signs Your Drain Pipe Is Frozen
Water changes from a liquid to ice at 0°C. However, when the weather outside reaches freezing, the water in your home’s plumbing doesn’t turn to ice immediately.
However, if the temperature stays below freezing for long periods, the water in your home’s drainage system can freeze.
Exposed drainage pipes and those laid in exterior walls will freeze faster. But what are the signs a drain pipe in your home has frozen?
Common signs that a drain pipe has frozen in your home include:
Water Won’t Drain
If water in a sink, shower, or bath doesn’t flow down the drain or drains away very slowly, it is a common indication that the drainpipe is frozen.
In some cases, this poor drainage can also be accompanied by frozen water pipes, which means either a trickle of water coming out of the tap or none at all.
Strange Noise From The Drain
If your drainage pipes are frozen, water must pass through this partially frozen drain. These thin pathways will cause peculiar noises, such as gurgling or bubbling, as the water struggles to flow through or around the ice formations.
Bad Smell
When your home’s drainage isn’t working efficiently, items you washed down the drain can’t escape. This means food scraps are trapped in your kitchen’s drainage, and hair or worse, are not flushed away in bathrooms.
Visible Frost Or Ice
In icy conditions, frost and ice might form on drainage pipes, which is a clear indication that the pipe is frozen.
You can also feel the drainage pipes for cold spots with the back of your hand.
But what should you do next if you’re 100% sure your home’s drainage pipes are frozen?
How To Safely Unfreeze Drainage Pipes
When you’re sure that your drain pipe is frozen, here are a few methods to unfreeze it safely:
Apply Heat
To unfreeze your drainage pipes, you need to apply heat generally to the frozen area. While pouring boiling water down the pipes might seem like a good idea, it can be a bad idea.
When boiling water is poured into a drain blocked by ice, it is doubtful it will melt a hole through. However, it is more likely to pool above the blockage.
If the blockage is close to the drainage point in the sink, shower, or bath, the boiling water (still boiling) could damage the PVC piping. Temperatures as low as 60°C can damage or misform PVC pipes.
But when the ice blockage is further down the drainage pipe, the cooled boiling water will most likely pool on the ice, drop in temperature, and worsen the ice blockage.
You must do the following if you want to use warm water.
Safely Using Warm Water
Throw table salt into the warm water to help unfreeze your frozen drain and lower the water’s freezing point. Salt lowers water’s freezing point, which means it will not freeze if pooled on top of an ice blockage.
According to the Met Office, seawater with a salinity, or salt content, of 35 parts per thousand (or 3.5%) will have a freezing point of around -1.8°C. The more salt you dissolve into the warm water mixture, the lower the freezing temperature.
The amount of salt you can add can vary depending on how much you want to lower the freezing point of the warm water.
To calculate how much salt you need to bring your warm water mixture to the salinity level of seawater of 3.5% for 1000 millilitres (or a litre) of water is a simple equation, which is:
1000 X 0.035 = 35. This means you will need 35 grams of salt
When you’re satisfied with the amount of warm water and its salinity level, slowly pour it down the drain. Don’t let the warm water mixture back up into the drainage area (e.g. the sink).
If this trick doesn’t work due to the size of the ice blockage, you will have salty water in your sink, which isn’t a problem but just annoying.
While this can potentially unblock minor ice blockages, it’s better to warm the drainage pipe via alternative methods.
Using A Hair Dryer
Use a hair dryer to apply heat to the frozen section of the pipe gently.
Make sure to wave the hair dryer back and forth over the area. Keeping it in a fixed position will cause hot spots, which can damage your PVC piping.
Also, when defrosting the pipe, heat the ice blockage from the drainage point (e.g. sink) to the frozen area and further along the pipeline.
While you can use a heat gun, be aware that it is far more powerful than a hair dryer and can cause more damage if not handled properly.
If you call a professional plumber to assist with your ice-blocked drainage, they will use heating tape. This heating tape is wrapped around the affected area and keeps it warm for an extended period.
Also, if your home is prone to drainage pipes freezing, a plumber can quickly install one for you.
Once the drain has been unfrozen, keep its surrounding area warm. This can be achieved by:
- Leaving the cupboard doors open to allow warm air in
- Place a heater close to the affected area
- Switch on an old-school incandescent light bulb (an element light bulb) close to the previously affected area
- Or wrap the warmed pipe in a blanket
Now that you’ve unblocked your drainage, how does a homeowner avoid this occurring in the future?
How To Prevent Your Drainage From Freezing
The best cure is always prevention. To stop your home’s drainage from freezing over, there are a few tips you can follow, which include:
Insulation
Installing insulation around your drainage pipes is a simple job that doesn’t require a professional. You can buy insulation sleeves from most hardware outlets.
However, if your drainage pipes are exposed to extremely low temperatures, you should have a plumber install electrical heating tape.
Dripping Hot Tap
If you suspect incoming cold conditions will freeze your drainage pipes, leave your hot tap dripping.
Flowing water does not freeze as quickly as stagnant water. Also, keeping the pipeline warm will help prevent the drainage system from freezing.
Keep Drainage Areas Warm
Ensure you keep your drainage pipes warm to prevent them from freezing.
You can do this by placing a heater nearby, keeping kitchen cupboard doors open, and simply allowing an incandescent light bulb to stay on.
But what if you’ve tried everything and nothing has worked?
Call In A Professional
If you’re wondering where to find a plumber during your coldest hour, WarmZilla can help you find one!
Feel free to contact one of our consultants if you need assistance.
Have a question? Please contact us on Live Chat
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