About 3,000 Fort Worth residents who used credit cards to pay their water bills online may have had their personal information stolen, the water department says.

A city contractor, CentralSquare, determined that someone hacked into the software used to process credit card information, water department spokeswoman Mary Gugliuzza said Thursday.

The customers whose data may have been stolen are being notified, she said.

The stolen information may include names, addresses and credit card data, including numbers and security codes and affects customers who made online payments between Aug. 27 and Oct. 23, she said.

CentralSquare is offering impacted customers free credit monitoring for one year.

Customers who had set up recurring payments by credit cards were not affected by the breach unless they changed credit card numbers online between August and October, Gugliuzza said.

Customers who paid by bank draft, by phone or in person also were not impacted.