Since the discovery of potentially harmful chemicals known as per- and polyfluoroalkyl substances, or PFAS, in drinking water in communities in Bucks, Montgomery, and Gloucester Counties beginning in 2014, The Inquirer has provided award-winning coverage of the issue. Follow this timeline, which will be updated as our coverage continues, to catch up on the latest.

Just getting caught up? Check out these stories first:

Nearly 400 military bases must be tested for drinking water contamination — and it will take years (April 21, 2017)

Timeline

2020

Air Force to give more than $2 million to stop contaminated water flowing from former Montco base

2019

New funding ahead for PFAS drinking water cleanup as legislature passes bill that will help Montco, Bucks

Relief is coming for some Bucks County residents with tainted tap water. But others are still waiting.

How three towns outside Philly became ‘trailblazers’ on clean drinking water