What Is The Best Way To Seal A Leak On A Threaded Pipe?


Best Way to Seal a Leak on a Threaded Pipe

No one wants to deal with leaky pipes; it wastes water, makes a mess, and just looks bad. But, when you have connections that use fittings and threaded pipes, you can inevitably end up with leaks. Primarily, leaks occur because no one used the proper sealant (or no sealant) during installation or the sealant’s worn out.

If your threaded pipe leaks, you can try things like epoxy putty or waterproof duct tape. However, these solutions are only temporary, and you need a more permanent solution to stop the leak for good. You need to redo the connection; of course, the best way is to ensure a proper connection in the beginning.

If you notice your threaded pipe leaking at a connection, you can always attempt tightening the connection first. This is because connections can tend to loosen a bit over time due to use and other factors. However, if the leak persists, you’ll need to move on to other options, which might include calling a plumber.

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Is the Leak from a Threaded Pipe Connection?

Depending on the severity of the leak, it may be obvious immediately or present itself over time. If you don’t notice an apparent leak, look for dampness or puddles forming on the floor below the pipes.

If there is no other water elsewhere, then the puddles are likely coming from a leaky connection. If you suspect a leak, feel the pipe around the fitting, you’ll feel wetness. Then, dry your hand and feel up further on the pipe. If this part of the pipe is dry, then you know the leak is coming from the connection. If the rest of the pipe has water on it, the water could be coming from elsewhere. Then, it runs down the pipe, appearing to be leaking from the connection. 

Again, in more obvious cases, you might see the leak coming from the connection. However, even then, it’s worth making sure it’s not water coming from elsewhere and simply dripping from the connection point. 

Either way, place a bucket under the drip to protect your floor while you plan your next steps.

How to Temporarily Seal a Leak on a Threaded Pipe

If you’re short on time, you can attempt a temporary fix to stop the leak. Quick fixes can work in a pinch until you can perform a more permanent solution. However, don’t expect them to hold up for long. Here are a few ways to stop a leak quickly. You can buy yourself a little time before tackling a larger project (or waiting for a plumber).

Create a Temporary Seal with Epoxy Putty

To temporarily seal a leak at its source, apply epoxy putty to the area. You can find epoxy putty for between $5 and $7 at home improvement stores or online. 

First, turn off the water supply and drain any water from the damaged pipe. Next, clean the area thoroughly and let it dry entirely before applying the putty.

Knead the putty to make it pliable, ensuring you apply enough material to cover the whole area surrounding the leak. Since various products can require different applications, ensure you read the instructions carefully for the putty you’ve chosen. Allow the putty to cure for the recommended time in the instructions before turning on the water flow. 

Finally, once you’ve turned the water back on, check for leaks. You might need to use more epoxy or try a different method if the leak persists.

Use a Pipe Repair Kit for Emergency Leaks

You can purchase a pipe repair kit for about $12 to $15 for an alternative temporary solution. Look for a kit that includes a waterproof fiberglass tape fit for repairing emergency leaks. 

Before applying the tape, shut off the water and ensure you’ve carefully read the directions. Wrap the tape around the connection with the leak, overlapping it as you go. 

You can use waterproof duct tape for a speedy fix (but don’t plan on it lasting too long). A 10-foot roll costs about $12 to $14 at most home improvement stores or online. Simply turn off the water and dry the area, then wrap it as many times as needed with the tape.

How to Seal a Leak on a Threaded Pipe (Permanent Solution)

As previously mentioned, the best way to seal against leaks on threaded pipes is proper installation. However, sometimes you’ll need to deal with old pipes or faulty connections (i.e., cleaning up someone else’s mess). In this case, you’ll have to redo the connection.

Tools You Need for the Job:

  • Bucket
  • Adjustable wrench
  • Slip-joint pliers or pipe wrench
  • Penetrating oil
  • Wrenches
  • Rag
  • Flexible supply tubes
  • Pipe joint compound (pipe dope) 
  • Teflon tape

Step 1: Prepare the Leaky Pipes

Before you begin, shut off the water supply to the pipes. Next, loosen the connection either by hand or using the wrenches. If it is challenging to loosen the fitting from the pipe, use some penetrating oil to soak it first. 

Then, drain any water from the pipe into a bucket, and clean the area around the leak. Let the entire area dry completely before proceeding. 

Step 2: Apply the Pipe Sealant

Using Teflon tape, wrap the male threads of the pipe in a clockwise motion, about 3 to 5 times. Then, apply a small amount of pipe dope to the tape, providing extra protection.  The threaded end of the pipe should face you as you wrap it.

Note: If you’re dealing with PVC pipe, you might prefer only to use pipe dope. If so, move on to step three.

Step 3: Tighten the Pipe Connection

Begin by tightening the fitting onto the pipe by hand. Then, hold the pipe with one wrench as you use another to tighten the connection. You want to keep going until you can’t go anymore, but don’t overtighten. 

Use a rag to wipe away any excess pipe dope coming out of the connection. 

Step 4: Turn on the Water and Check for Leaks

Once you’ve tightened the connection, turn the water back on and check for leaks. You might need to readjust or tighten your connection if you still notice any drips. If the leak continues, it’s best to call a plumber (or you may need to replace the pipes themselves).

Considerations When Choosing the Right Sealant for Threaded Pipes

As you can see, a proper and permanent leak repair relies heavily on using the correct sealant. But, not all sealants are created equal. Certain types of sealants work better for various applications. 

In a nutshell, you can find Teflon tapes (PTFE tapes), pipe dope, and anaerobic resins. In this article, Teflon tape and pipe joint compound worked together to seal the leak. However, it also mentioned not using Teflon on PVC pipes (see the next section for why). 

PTFE Tape

PTFE stands for polytetrafluoroethylene, but people more commonly use the trade name “Teflon.” Teflon tape is very flexible, making it easy to apply to a variety of metal threads. You can find Teflon tape in different versions for water, gas, or air. 

Many pros don’t recommend using Teflon on threaded PVC pipes. This is because it can make the threads too wet, resulting in potential overtightening and damage.

Pipe Joint Compound

Also called pipe dope, this sealant is by far the most versatile. It’s a paste or putty that you brush on, and it is very effective in many different circumstances. These compounds don’t fully set, allowing them to retain some flexibility to help cope with movement or changes in pressure.

Although it’s not as easy to use as Teflon tape (and pricier), it’s the favored choice of most professional plumbers. You can use it on metal or plastic threaded pipes. 

Anaerobic Resins

These types of sealants are best for specialty repairs or applications as opposed to general repairs. This is mainly because they are the priciest option and can take 24 hours to fully cure. Plus, they don’t work well with plastic and can only cure when no air is present. 

However, these sealants provide some of the strongest, longest-lasting seals. 

No matter what sealant you end up using, it’s essential to pay attention to what type of pipe it’s best suited. Make sure to read the packaging carefully on any sealant you choose. Also, take note of the temperature and pressure thresholds for the sealant. 

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Related Questions

How much would a professional plumbing repair cost for a leaky pipe?

Most plumbers charge by the hour, anywhere from $50 to $100, or more. However, when it comes to fixing leaky pipes, a lot depends on the location of the leak. For example, if it’s an exposed pipe below your sink, it could be a pretty quick job. 

However, if it’s a pipe in the center of a tight crawl space, it’s likely to cost more. You could pay between $150 to $600 or more for a leaky pipe, especially if the plumber discovers more leaks. 

But, on the other hand, getting leaks fixed properly can ultimately save you a lot of money and headaches. Conversely, leaving a leak unrepaired can lead to significant property damage and higher utility costs. 

What if the pipe connection keeps leaking after applying Teflon tape and joint compound?

Sometimes, even after doing a stellar DIY job to fix a leaky threaded pipe, it still leaks. So before you hang up your DIY cap, don’t despair. It could be your pipes, or more pointedly, the threads. 

Over time, pipe threads can wear down, or it’s possible they were never in good shape. This is especially the case if someone cut the threads with a worn-out pipe threader. Therefore, if the leak is still there after your repair attempt, you might need a replacement pipe or fitting. 

Stacy Randall

Stacy Randall is a wife, mother, and freelance writer from NOLA that has always had a love for DIY projects, home organization, and making spaces beautiful. Together with her husband, she has been spending the last several years lovingly renovating her grandparent’s former home, making it their own and learning a lot about life along the way.

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