Is Your Sewer Causing Sinkholes?

Sinkholes can develop naturally when rock below the surface of the land dissolves or erodes due to water circulated around it.  When enough of this area has eroded away it is unable to support the earth above it and the earth caves into the cavity below, causing a sinkhole.  Sinkholes can also develop due to man-made circumstances.  If you have ever looked at a house and noticed a depression or a trench in the front lawn, chances are the sewer is running directly below that depression.  A sewer line that is not sealed properly can cause the ground to erode over time, leading to your sewer causing sinkholes.

Years ago, the joints of sewer pipes were packed with a rope like material called oakum and then wrapped with a layer of concrete around the outside of the pipe to seal it.  Over time, the concrete and oakum in these joints deteriorates, causing the sewer line to leak. Today’s building codes require sewer lines be gasketed and sealed properly so that water does not leak out of them (exfiltration) or that groundwater does not leak into them (infiltration). Both infiltration and exfiltration cause the soil surrounding the sewer line to erode, and as this erosion occurs, a sinkhole forms in the area above the sewer line.  Sinkholes pose many dangers to both people and property – cars driving over one can be damaged if the sinkhole is large enough or someone who unknowingly walks into one can turn an ankle or perhaps experience something even worse.

Many municipalities today now diagnose the cause of these sinkholes to be sewer related.  In order to test this, city workers position a camera in the city main sewer line while pouring colored water into the sinkhole. They can then determine which particular sewer line is causing the sinkhole by seeing the colored water flowing out of it and into the city main sewer line. In plenty of these cases, the municipalities are placing the responsibility on the homeowner to make the necessary repairs to their sewer line.  Often times, this usually means thousands of dollars in repairs and restoration costs for the homeowner.

Lining your sewer line seals off any joints or cracks where water may be leaking by creating a brand new one piece pipe inside your old pipe.  Lining stops water from leaking in or out of your sewer line and thus, stops the erosion that could possibly cause a sinkhole.