DeKalb County residents will see an increase in their water bills starting with those going out this month.

The 11 percent increase that took effect Jan. 1 is the second year of a three-year plan to raise rates to pay for a $1.35 billion overhaul to the county’s aging water and sewer system. Rates increase by 11 percent again next year as part of that plan.

The increase translates into about $7.14 more a month for the average customer using 5,000 gallons of water monthly. Before the three-year rate hike, DeKalb water rates last increased in 2008, when they went up by 16 percent.