As the Philadelphia Water Department seeks to raise rates by 12 percent over the next two years, the city will hold a series of hearings starting this week to get feedback from customers.

The rate increase, which must be approved by the water rate board, would be phased in starting July 1, with another bump on July 1, 2017. Over the two years, the average residential bill would go up by about $8 per month.

Water Department Commissioner Debra McCarty called the increase a "responsible request," saying additional revenue is needed to repair and replace aging infrastructure and comply with regulatory mandates, among other factors.

Community Legal Services, the public advocate appointed to represent residential customers in the rate case, said the impact on low-income customers could be significant. Rob Ballenger, a staff attorney for the nonprofit, said he is concerned that the department isn't using enough reserves to offset the increase.

The Water Department last raised rates in 2013, phasing in a 17.5 percent increase over three years.

This will be the first water rate case overseen by the newly established water rate board. Before the board's establishment, the water rate was set by the water commissioner, a process that critics said was one-sided.

The five-person board will now preside over the process, which will be led by a hearing officer. The board is expected to issue a decision in time for the new rate to go into effect, or not, by July 2.

The Water Department and rate board will seek feedback at five hearings:

6:30 to 8:30 p.m. Tuesday, White Rock Baptist Church, 5240 Chestnut St.

6 to 8 p.m. Wednesday, Philadelphia Protestant Home, 6500 Tabor Rd.

10 a.m. to noon next Tuesday, Central Library of the Free Library, 1901 Vine St.

6 to 8 p.m. March 2, Roxborough Memorial Hospital, 5800 Ridge Ave.

7 to 9 p.m. March 3, North Philadelphia YMCA, 1400 N. Broad St.