Pennsylvania American Water on Friday filed a rate request that would boost the bills of its Philadelphia-area residential customers by $9.49 a month, from $55.63 to $65.12, or 17 percent.

The request, filed with the Public Utility Commission, would generate $107.9 million a year statewide, or 16.4 percent across all customer classes. Pennsylvania American has 650,000 customers in 400 communities, including 44,000 in the Philadelphia suburbs.

The utility last requested a rate increase in 2013, when it sought a 10.1 percent boost. It settled for a $26 million increase, or 4.5 percent, that went into effect in January 2014. Friday's request is targeted to go into effect in January 2018.

The company said the primary reason for the rate request is to recover the $1.26 billion it will have invested in improvements since 2013.