What are the Causes of Under Concrete and Under Ground water Leaks?

• Poor Installation
• Hard Water
• Water Speed To Fast
• Water Speed To Slow
• Earth Movement
• Electrical Grounding Issues
• Aggressive Soil
• Wear, Tear and Old Age
• Banging Pipes at the Fixtures

Your home is not predestined to have a slab leak in the near future.

Poor Installation

Yep, most leaks in copper water piping under the concrete come from sloppy installation. The plumber steps on the soft copper pipe to straighten it from the manufacture’s packaging. The line is also bent when terminating it in a wall for the manifold connections. Sharp bends and dents in the piping cause turbulence and this turbulence causes the water to wear the copper piping through. If the entire pipe is not encased in a plastic sleeve the movements of the water piping will cause abrasions on the outside of the copper tubing wearing it out over time.

Hard Water

If your water contains too many grains of hardness it can scour the inside of the piping like the Colorado River has done when making the Grand Canyon.

Water Speed To Fast

The maximum recommended velocity of water in the copper piping is 7 feet per second. Faster than this means that the water will take some of the copper along with it each time it is being used. This is especially true on water circulation systems. Continuously moving water from a pump that is too powerful will destroys the piping over time.

Water Speed To Slow

When the water speed of the hot water system is moving too slowly the mineral deposits tend to stick together and become heavy. They can then stick to the sides and bottom of the piping forming dams. As the water rushes around these dams the water speeds up and erodes the walls of the piping about an inch or so from the dam.

Earth Movement

Earth movement is not just about the house sliding down a hill here in Southern California. The earth moves if you have expansive soil conditions. Expansive coil conditions come from soil filled with clay. As the clay rich soil absorbs water (rain-sprinklers-etc) it expands and can actually lift the foundation of the home. Most new homes that are located in expansive soil conditions have Post Tension Slabs. Earth movement also results when the home expands during the course of the day and then contracts at night. It is not unusual for a home to grow a couple of inches throughout the day in the heat of the sun.

Electrical Grounding Issues

The copper water pipe system of your home is directly connected to the main circuit breaker panel grounding system. The neutral and grounding buss bars are connected together and to the gas line, water line and potable water system. If a grounding or neutral system is connected at some place other than at the main panel in the home the result could be electrifying the copper piping. You won’t know it and you won’t typically get shocked, but what happens is the pipe internally corrodes and grows little green stalactites and stalagmites. These end up developing into pin hole water leaks.

Aggressive Soil

Many of the area around the county have been home to dairies in the past. The soil becomes acidic after use and the placement of unprotected copper water piping under the foundation causes a reaction that tears up the copper water tubes and produces multiple leaks. Some of these soil conditions will also destroy the concrete foundation of the home.

Wear, Tear and Old Age

Every time you turn a faucet on the water moves throughout the copper water tubing in your home. This causes vibrations to form and these vibrations force the piping to move back and forth against the soil they are buried in. This can wear out the surface of the piping. Water circulation systems tend to wear the piping out quicker as more water is forced down them. It is a common misperception that a water circulating pump increases the pressure of the water in the piping. Circulating pumps have no significant ability to increase the water pressure. Nothing lasts forever.

Banging Pipes at the Fixtures

Banging water pipes typically occur as a result of excessive pressure, poor strapping and a defective faucet or valve washer assembly. It can occur for all of those reasons or just one of those reasons. The most often cause is a loose washer in an angle stop, toilet shut off valve or faucet. When the loose washer moves back and forth it essentially turns the water on and off constantly. This movement causes the water to suddenly stop and start. This is what causes the banging. This banging can destroy the water system and mush be addressed.

High Water Pressure Does Not Cause Slab Leaks

There are 3 main thicknesses of copper water pipe in a home. They are Type M , Type L and Type K. M is thinner and used above grade and L is thicker and used below grade. We cannot develop enough water pressure to cause a water pipe to burst. M type copper will burst at or around 3600 psi. The average household here in Southern California runs at about 55 psi and must have a pressure regular if the psi exceeds 80 psi. The highest I have ever seen water pressure is 175 psi in the hills in some newer build out areas. The fittings are all type K copper which is even thicker yet.

Here is the Study Results for Copper Piping Pin Hole Leaks in .pdf format