This year sinkholes are popping up in California at a higher rate than usual, thanks to the wet winter we experienced earlier this year. One sinkhole even caught a school bus!

(Don’t worry, no one was hurt.)

Since sinkholes are relatively rare in California, some customers have asked us, “can a water leak cause a sinkhole?”

Yes it can.

In fact, the combination of a wet winter and a leak in your plumbing can make a sinkhole develop faster. Here’s how it happens and the signs you should look out for to catch a sinkhole before it becomes a safety hazard.

How Do Water Leaks Cause Sinkholes?

Sinkholes are caused by water eroding the ground underneath your home. The ground beneath your home isn’t all solid. If you dug far enough down, you’d eventually find pockets of air, or pockets of water (called the water table.) The ground is still stable despite these gaps unless large amounts of water pour in and move the dirt around.

If there’s a water main leak, or even if you have a major leak in your home, the excess water can erode your ground. If enough dirt is moved, the ground collapses into the gap. From our vantage point on the surface, it seems like a whole section of the ground suddenly drops down, even though it has been eroding for some time. That’s why leak detection is so critical, to prevent sinkholes.

Right now, as California’s water tables are fuller than they have been for a while, there’s a lot more movement going on underground than there normally is. Further, we also have a lot of sand-like soil. Sandy soils have much smaller particles than clay soils or other types of dirt. It’s easier for these small particles to be moved around by a sudden rush of water.

Sinkholes can also be caused by dissolvable rocks, such as rock salt and limestone. These types of rocks are more easily swept away by water. California doesn’t have much of these rocks, so sinkholes aren’t as common here as they are in other areas.

The Signs of An Underground Water Leak

Given the rise of sinkholes, it’s wise to know how to spot a sinkhole on your property before the ground gives way. Here are the signs:

  • Cracks in the foundation
  • Cracks in your driveway, sidewalk
  • The home seems to lean
  • Doors won’t close properly
  • Areas on your lawn are greener or browner than normal
  • Your water bill is much higher than normal
  • Water pressure has dropped off significantly
  • You can hear running water when you shouldn’t

In most circumstances, it will take a very serious leak to create a sinkhole, unless the water conditions beneath your home are very unusual. That’s why sinkholes are more common below city water mains, which can deliver huge amounts of water quickly.

There will typically be many warning signs of a sinkhole on your property before it falls through. However, as sinkholes are so damaging and dangerous, if you suspect your property may be developing one, you should get expert help from a trusted plumber right away.