EPHRATA - Grant County PUD commissioners listened to the public's thoughts about rate increases on Monday and Tuesday.

It's already known rate increases are occurring next year, but it hasn't been decided how the increases are going be spread across different customer groups.

Commissioners approved increases in 2010, with rates increasing by 4 percent in 2010 and 6 percent in 2011.

Next year, the proposed average increase for residential customers is about $6 per month, said Sarah Morford, a district spokesperson.

Each rate group has a different revenue increase proposed, from 8 percent to 12 percent, she said.

The proposed increase amounts are because of the increasing operating costs for the dam's federal license and work done to replace aging turbines and generators.

The work increases the PUD's debt level. By 2015, the district will have accumulated $1.3 billion in debt, Morford said.

Rates must be increased to cover the cost of borrowed money and increased operating costs, she said.

The proposed increases are:

* Irrigation and ag food processing boiler - 8 percent

* Large industrial - 8.2 percent

* Large general users - 10 percent

* Industrial and ag food processing - 12 percent.

Other utilities, including Chelan County PUD, Douglas County PUD, Seattle City Light and Tacoma Power, plan to raise rates next year, Morford said.

The next step for Grant PUD is to adopt rate schedules on Sept. 6.

If approved, increases start Jan. 1.

Next week's hearings both start at 6 p.m.

Monday's hearing is held at PUD headquarters in Ephrata, at 30 C St. SW.

Tuesday's hearing is at the district's Moses Lake office, 312 W. Third Ave.