HARLINGEN – Harlingen Water Works System crews are in the midst of a process to fill in an unexpected sinkhole.

The utility was alerted to the problem and responded early Tuesday morning.

The sinkhole appeared under a well-traveled residential street on Haverford Blvd.

The supervisor of the crew from Harlingen Water Works System said it could take one or two days to cap the sinkhole.

He said Harlingen deals with a legacy of aging clay pipes that were installed decades ago. His best guess at the moment is a clay pipe sprung a leak years ago and gradually washed away the soil.

Harlingen Water Works System expects to fill in the hole with a mix of cement and sand called backfill. The pipe will also be replaced.