A contractor renovating Ashbridge House in Rosemont recently uncovered a 200-year-old underground cistern while working on the $5 million project, writes Richard Ilgenfritz for Main Line Times & Suburban.

The discovery, made beneath a garden patio’s bluestone pavers, prompted immediate consultation with Lower Merion’s historic preservation planner and the township’s Historical Commission.

The cistern is approximately 30 feet deep and 40 inches wide. It was examined using a sewer department camera, revealing a stone-lined, dry-laid well with potential centuries-old debris at the bottom. However, its location conflicts with the foundation of a planned building addition, making preservation difficult.

Following recommendations from the Historical Commission, township officials approved a plan to partially fill the cistern. The lower two-thirds will be stabilized with sand and lean concrete. The upper portion, which interferes with construction, will be removed. The well will be documented through photographs, measurements, and detailed notes.

To honor the site’s history, the township will consider adding a circular inlay, plaque, or exhibit marking the well’s former location. A subcommittee will oversee this effort and handle any additional historical finds during construction.

Despite the historical significance of the find, the commissioners ultimately prioritized the renovation plans.

Read more about the centuries-old cistern in Main Line Times & Suburban.

Editor’s Note: This post was originally published on MONTCO Today in February 2025.