To help fund water line improvement projects next year, the top water-using customers of the Greenville Municipal Authority will find themselves shelling out additional cash next year.

Customers who use more than 8,000 gallons of water per billing cycle -- that is, every two months -- will pay 6 percent extra for their water bills.

Most of the water company's customers, said superintendent Bill Brady, use fewer than 8,000 gallons every two months.

The water authority has a tiered rate card, with larger consumers, such as Thiel College and UPMC Horizon, paying less for each gallon of water. The college, hospital and a car wash each buy more than 668,000 gallons per cycle, Brady said.

Nearly 1,700 of the authority's customers will not be affected by the rate increase because of their lower water usage rate.