Slab Leaks


Is your water or gas bill going up without an obvious reason? This could be an indication of a slab leak? What is that? Copper water pipes are located just below the concrete slab when the house was built, if you have a concrete slab floor. Poor quality or incorrectly installed copper pipe might develop a pinhole leak and you not know it. To test for a leak – make sure anything that uses water in your house is shut off. That means all hoses shut off completely, all faucets turned off and make sure none of your toilets are running. Next, make your way to the water meter usually located at the curb. Open the meter box and view the face of the meter. Most meters will have a red triangle on the face that will show small amounts of water usage. If that triangle is spinning, water is being used somewhere in your house. If not, you do not have a leak.

To isolate the leak is, turn off the water main valve at the house. If your valve is a gate valve (round handle), this valve is known to leak and should not be considered a positive shut-off. If the valve is a ball valve (lever handle), you can feel good the water is shut-off when you turn it off. If the water meter triangle moves when you shut off your water main valve at the house, then the leak is in the water main in route to the house. If the triangle stops, then the leak is beyond the water main valve. Open the water main valve again and turn off the valve above the water heater. Again, if it is a ball valve, you can feel good you are shut off completely. If the triangle shows movement once the water heater is shut off, your leak is under the slab in the cold water line. If shutting off the water heater stops the triangle from moving, the leak is in the hot water line under the slab.

What to do if you have a slab leak. Call a plumber you know and trust. Con-artists can run up your bill into thousands of dollars. It is nearly impossible to estimate this type of repair until you actually locate the leak. A good plumber will keep you informed thru the entire process and give you advice along the way. Most of my slab leaks have not required the removal of cabinets and have been under $2,000.00. It might be advisable to contact your home-owners insurance if the costs are on the high end.

Is this the first leak, or have there been several in a short period of time? A good indication of needing to repipe rather than repair would be multiple leaks over a short period of time. Also, if your leak is located in a post-tensioned slab, you must repipe as breaking up this type of slab would disturb the stability of your home’s foundation.