Can You Pour Boiling Water Down The Drain?

Last Updated On June 22, 2024

Updated on November 26, 2023

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Can You Pour Boiling Water Down The Drain

A stubborn, backed-up drain can wreak havoc on your home life. 

When you are faced with a drain back-up either due to soap scum, dirt and debris, or hair, you may be wondering what you can do to clear the drain. 

You may wonder if you can pour boiling water down the drain.

By the end of this article, you should have a clear understanding of why this practice could potentially harm your plumbing system, and what you can do instead.

What's In This Guide?

      What Happens When You Pour Boiling Water Down the Drain?

      While it would be nice to avoid scum build-up in your pipes, sometimes it can be hard to avoid this. 

      One way to potentially remove this build-up is by using hot water and soap. 

      The theory behind this is that hot water and soap are great at removing fat, dirt, and grime and flushing it down the drain. 

      When you combine boiling water with soap, the water melts the soap so that it can latch onto the fats and other grease that build up in your pipes.

      The question is, should you do it?

      Should You Pour Boiling Water Down Your Pipes?

      Are you dealing with a stubbornly slow drain and have come across the age-old ‘hack’ of pouring boiling water down the drain? 

      While it can seem like the most obvious and convenient solution, pouring boiling water down the drain can have consequences.

      You likely should not pour boiling water down the drain. This is different from hot water which has not reached a boiling point. 

      You can of course pour hot water down a drain to attempt to clear it.

      Also, know that you can safely pour hot water down your drain even if it is connected to a city sewer line or a residential septic system.

      However, you may want to look into cleaning techniques based on your system.

      Can You Pour Boiling Water Down The Drain To Loosen Clogs

      Whether you should pour hot water down your pipes will depend on the material your pipes are made from. 

      Common Types of Plumbing Pipes

      There are several different types of plumbing pipes

      However, these three are more commonly used in residential plumbing:

      • PVC – Polyvinyl Chloride Pipes (a thin-walled type of plastic that is usually white)
      • ABS – Acrylonitrile Butadiene Styrene (a thin-walled type of plastic that is black) 
      • Metal – A commonly used material in older homes (cast iron, copper, galvanized steel)

      It is easy to tell the difference between plastic and metal. 

      To identify the material of your pipes, look under the kitchen or bathroom sink. 

      • If you see a white or black plastic-looking pipe, it is likely a PVC pipe or ABS pipe. This means that it is plastic. 
      • If it does not look like plastic, then it is metal like copper or galvanized steel.

      Over the years, you may have had repairs done to your home. If you have made repairs to your plumbing, like replacing your P-trap, it is probably a plastic material.

      You might have a mixture of materials used for your wastewater pipes. 

      If you have a basement or access to your crawlspace, you can take a look down there to see what types of pipes you have. 

      The Impact of Boiling Water on PVC vs. Metal Pipes

      If you have a plastic pipe, and the water is flowing well (in other words, not clogged) it is safe to pour boiling water down the drain. 

      But, if you have a clogged bathtub drain (slow-moving or completely blocked drain) you should NOT pour boiling water down the drain. 

      The truth is that boiling water can damage plastic connections. It’s simply not worth the potential long-term damage and expensive repairs. 

      If the pipes are metal, pouring boiling water down the drain is fine.

      If you’re certain all the pipes are metal, here’s how to clean cast iron pipes.

      Never pour grease or oil down the drain. 

      Does Pouring Boiling Water in Toilet Remove Clogs?

      This has the potential of deforming the wax seal or even cracking the bowl. And it won’t provide much benefit to removing the clog. Try a plunger first.

      Can You Pour Boiling Water Down The Drain To Unfreeze Pipes?

      Typically, it’s your supply line that will freeze. And there’s no way to pour water down that water pipe. 

      If it’s a clogged drain, it will not do much unless the clog is in a small area like a P-trap (drain trap).

      Recap: Can You Pour Boiling Water Down the Drain? 

      Pouring boiling water down the drain will probably not hurt if done occasionally. However, it is important to exercise caution and wait for it to cool. 

      Boiling water can help dissolve soap scum, grease, and other debris that may accumulate in your pipes over time. But it’s not an effective drain cleaner (try a natural drain cleaner). 

      Remember to use boiling water only on metal or ceramic pipes, as it may damage plastic pipes. 

      And remember to check back at Plumbing Nav for all your DIY plumbing service needs.

      FAQs to Answer: Can You Pour Boiling Water Down the Drain?

      Can I pour boiling water down my kitchen sink?

      Yes, but we don’t recommend it. Let the water cool down first so it is hot and not boiling.

      Will boiling water damage pipes?

      It can, depending on the materials your pipes are made from. If they are plastic, boiling water could damage them. Play it safe, and wait till the water cools down.

      Can you pour boiling water down the drain to loosen clogs?

      Yes, you can, but you probably don’t want to. It usually isn’t effective and can damage pipes. If you need drain cleaning, there are better and safer methods for fixing a drain clog.

      Is it safe to pour boiling water down a shower drain?

      It depends on the kind of drain pipe you have. A much better way is to use a simple drain snake to remove shower drain clogs.

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      About Plumbing Navigator

      We write about "all things plumbing," helping you navigate common questions, repairs, and the best plumbing products on the market.

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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