How to Fix a Slab Leak on Your Own

When a slab leak strikes, it can cause a lot of damage to your home – quickly. Your slab is a single piece of concrete that serves as the foundation of your home. Once it develops a leak, it can cause problems around your entire house. And, it can be incredibly expensive to fix.

Many homeowners believe that their insurance will cover the cost of repairing their slab leak. Unfortunately, many of them are shocked to find out that their insurance policy only covers the house – not the slab that lies underneath it. If something goes wrong with your slab, in most cases, you are on your own.

How can that be?

Most homeowner’s insurance policies cover your house and everything inside. So, if a slab leak floods your home and ruins your carpeting, your insurance will pay for new carpet. However, they will not pay to actually fix the slab leak. Getting a slab leak can turn into an expensive insurance lesson for many homeowners!

That’s why so many homeowners want to fix slab leaks themselves. After all, who has thousands of dollars to pay to a plumber?

It doesn’t take a professional plumber to fix a slab leak, though. In fact, you can do the job yourself, by following these 7 tips:

1. Figure out exactly where the slab leak is.
Many times, you can feel a slab leak. If a hot water line is leaking, you will feel a warm spot on your floor. Or, if your carpet is suddenly damp, you know you have a slab leak. If you can pinpoint exactly where the leak is, you’ve overcome the first hurdle.

However, not all slab leaks are easy to find. You may have to call in a professional to locate your slab leak. They have special tools that can find a leak, without ripping up the floor. But, even if you call a professional in to find the leak, you can still repair it yourself.

2. Once you find the leak, shut off the main water supply to your home.
Plumbing repairs are tricky – especially for non-professionals. If you do make a mistake, you don’t want to flood your home. To be safe, shut off the water.

3. Remove the flooring above the leak.
Many times, you can get away with removing a single tile; it just depends on how big the leak is. Usually, you will just need to remove enough of the floor so that you can fit your hand and some small tools in to fix the leak. And, you don’t need fancy equipment to remove the flooring. In most cases, a concrete drill bit will do the trick. The vast majority of foundations are about 4 inches thick, so make sure your drill bit can handle something that thick.

4. Now, it’s time to repair the pipe.
How you actually go about fixing the pipe is up to you. There are several methods that all work well:
- You can get special pipe wraps that are designed to stop leaks, that work just like a bandage.
- You can get a special epoxy that will seal the leak.
- You can patch up the leak by soldering the pipe.

5. Once you think the leak is sealed, turn the water back on.
It’s time to see how well you did. If the leak isn’t sealed properly, you will see water coming out of it as soon as you turn the water back on.

6. Leave the pipe exposed for a few days.
Even if you think the leak is totally sealed, don’t replace the flooring just yet. Instead, leave the pipe exposed for a couple of days, so that you can keep an eye on it. Some slab leaks are very slow; you may not see any evidence of it right away. The last thing you want to do is put the floor back together and discover that the leak isn’t totally gone!

7. Replace the flooring.
You will need to pour new concrete over the pipe, give it time to dry, then put the flooring back together.

11 Responses to How to Fix a Slab Leak on Your Own
  1. 800 Plumbing
    February 15, 2011 | 5:32 am

    This seems easy enough to DIY, however if you are the least bit doubtful, always consult a professional.

  2. craig
    September 24, 2011 | 1:14 pm

    can u replace a bad spot of copper line [ water] with a rubber line and clamps?

    • matt
      April 11, 2012 | 11:45 am

      no

  3. mike
    October 14, 2011 | 5:48 am

    Issues with water pressure coming out of the two downstairs sinks when the toilet fills up with water.. When the toilet fills up the water pressure returns to the normal flow out of the sinks when turned back on.. Water regulator is fine.. When you do not flush the toilet there are no water pressure issues?? Suggestions? Ideas?

  4. clive
    October 27, 2011 | 3:15 pm

    the general rules a) mechanical joints should never be buried in an inaccesible place. i.e. under a slab. b) all joints under a slab should be brazed, not soldered. the reason being, a soldered joint is far more brittle than a brazed joint and has the potetial to fracture in the event of any ground movement.

  5. David
    December 26, 2011 | 4:46 pm

    @clive: IMO soldering and brazing are the same thing… you’re joining using a metal that melts at a lower temperature than the base metal (in this case, copper). Possibly the only difference you’re referring to might be the type of metal/solder that you’re using, and the temperature at which it melts.

    • 3rd-gen plumber
      January 21, 2012 | 8:12 pm

      soldering and brazing are not the same thing! … they are very similar … but not the same.

      Brazing vs. Soldering
      Brazing – The American Welding Society (AWS ), defines brazing as a group of joining processes that produce coalescence of materials by heating them to the brazing temperature and by using a filler metal (solder) having a liquidus above 840°F (450°C), and below the solidus of the base metals.

      Soldering – Soldering has the same definition as brazing except for the fact that the filler metal used has a liquidus below 840°F (450°C) and below the solidus of the base metals.

      check it out!! http://www.lucasmilhaupt.com/en-US/brazingfundamentals/brazingvssoldering/

  6. 3rd-gen plumber
    January 21, 2012 | 9:31 pm

    Sometimes, things are easier said than done. The average home owner should no more try to repair his own slab leak than he should opperate on himself.

    First of all… a leak can ocur anywhere along the route of the pipe and can sometimes be very hard to find. Sometimes even the best leak detection companies throw there hands up and give up. there are just too many variables to list. Its ludacris to try to put leak detection instructions in a nice little box and hand it to a home owner and expect them to be successfull.

    Second of all … there are plumbing codes that need to be fallowed for the protection of us all! A Right Way and many wrong ways.

    The only code approved way to repair a copper pipe below slab is to use apropriate copper fittings and Braze the joints!!! Solder is not legal below slab and is not the same as brazing.

    ****** California Plumbing Code section 609.3 , 609.3.1 , 609.3.2 ******

    Thats why the copper tubing was rolled in under the slab in the first place…. no joints below slab and it was labor saving.

    Rubber patches, clamps, epoxy, mechanical unions, and Shark-Bite fittings are not approved methods for copper leaks under slabs.

    If you don`t fix it right the first time… there will be a second time …. and who knows what the damage will be?

    Even Lazy plumbers resort to easy fixes if it will help them make a buck.

    Find a professional plumber that you can trust …who knows the code… and wont take short-cuts.

  7. Mrs. Cantu
    March 19, 2012 | 5:28 pm

    Ihave an old home buit in 197o’s. The wanter in my bathroom sink does not drain eaisly. Had plumber come out and he said that he could not see the problem anywhere. Thinks I have to call a specilist to check for leak under slab. Do not know what to do. Have no money for major repairs. Have home owners insurance but not home warranty insurance. Any idea what this will entail and cost? Mrs. Cantu

  8. Jared
    April 18, 2012 | 11:57 am

    After having a slab leak, this is not something I would ever attempt to repair on my own, nor do I own all the tools needed. I called my plumber…if you are in the Dallas area, http://www.totalplumbing.net does great work.

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