The #1 Cause of Foundation Failure in Southern California

If you have been watching the news about earthquake preparedness and all the recent seismic activity in California, you’ll quickly realize none of us paid any attention to that old adage about building a home on a solid foundation, because that one surely doesn’t ring true in our neck of the woods. If you live in Southern California, you know you’re living on shaky ground, and there is not much you can do about that, except move. When the big one hits, a lot more than our foundations will be rocked… that’s for sure. You can bet, if its anything like the movies, we can assume most, if not all, our homes including the foundations they are built upon will experience considerable damage if not total destruction.

But, did you know that seismic activity, (earthquakes), is not the number one reason for foundation failures in Los Angeles? Water is, in parched, drought stricken Southern California! Go figure…

That’s right water. Too much, or too little, in the soil below can and will cause your home, or just about any structure (foundation) attached to the ground, to settle or possibly heave (lift) depending on the amount of water and the type of soil your home is built on. The caveat to this; if your home is built on solid rock (most aren’t) you probably won’t have a problem anytime soon, but I wouldn’t bet on that one. There is a whole list of other problems to worry about.

Unlike the soil beneath your foundation, water does not compress, and when excessive amounts of water seep into the ground beneath your home, any soil with a moderate amount of clay content begins to swell.

That condition is known as “expansive soils”. Although Southern California does not experience the extreme expansive conditions that other parts of the country have, there are many areas where the clay content is high enough to cause considerable damage when excessive water is present. In the instance of non-swelling soil types, like sand or decomposed rock, an overabundance of water can fill the small voids between the sand and rock particles and cause movement and/or considerable damage like it did in this extreme example of an in-ground pool lifted due to excessive ground water.

In dry conditions, like we have been experiencing with the unprecedented drought in California, expansive clay soils beneath your home begin to shrink away and settle under your foundation. For a good example of how your soil can behave when it dries out, just look at that sponge you left on the sink to dry. Eventually, the sponge is half the size of what it was when wet. The soil under your foundation does exactly the same thing, leaving your foundation to settle and fall right along with the ground beneath it. Cracks and other symptoms soon ensue. If left unchecked, the settlement will eventually cause severe and often irreversible foundation and structural damage.


Poorly designed yard irrigation or the lack thereof, leaky pipes and sewers, your neighbors’ watering habits, living at the bottom of a hill where water runoff is evident, the El Nino phenomenon, and of course, the lack of water as our state begins to dry up, is a major concern. Too little water can be just as damaging to your foundation as too much water.

The Number One Culprit for Foundation Failure in Los Angeles

The number one main source of foundation failure we see in L.A., is leaking sewer pipes. Most people don’t even give their sewer pipes a second thought until the pipes back up, usually on Thanksgiving or during a large family gathering. Don’t you love it when that happens? And it happens a lot! You see, if you take a shower, or run the washing machine and all the water disappears down the drain, who’s to care? Remember though, we live in an active earthquake zone. The ground beneath our homes is always on the move and so are our pipes! If the ground moves, so does the sewer lines. Trees and roots can also cause sewer lines to break or separate leaking 20% of you daily usage right under your foundation. Remember that sewer clog you had fixed? Chances were, it was that tree in your front yard causing the lines to get plugged up. It’s all clean now, so where do you think the water is going from all those showers and laundry cycles? Now you know why that tree always looked so good, you were watering it daily. Think about it. If just twenty gallons per day was leaking under your home, how wet do you think the ground could get over a two year period? Pour that amount in your garden and step into the mud and see what happens. Your house is just a bit heavier.

Water isn’t the only culprit

We know water isn’t the only culprit. There are many other factors and conditions that can cause your foundation to fail. Poor compaction, tree roots, and erosion can also contribute to foundation issues. The U.S. Geological Society recently reported that each year foundation damages cause more dollars lost than both Hurricane Katrina and Hurricane Sandy combined. One in four homes in America will experience foundation damage that will cause thousands of dollars to repair. Left unchecked, the damage and costs continue to skyrocket. Bottom line: It’s a good idea to pay closer attention to that thing your house is built on.

Are you the next victim of foundation failure?

Don’t be! Have your foundation checked by one of our professionals. Want to know more about the signs, the symptoms, and the solutions that may be cause for concern?