Customers of Aqua Ohio, the state's largest investor-owned drinking-water and wastewater utility, will see lower bills starting this month, the result of federal tax cuts.

In December, the Public Utilities Commission of Ohio authorized the company to credit customer bills based on the impact of the Tax Cuts and Jobs Act of 2017, which reduced the top corporate income tax rate from 35% to 21%.

Aqua Ohio, whose rates are regulated by the PUCO, will credit both water and sewer customers the amount it has overcollected, plus interest, since Jan. 1, 2018, under the previous corporate tax rate. The combined $4.8 million credit will be passed back to all customers over a 12-month period.

"We're saving money on the tax side, and we're passing it on to customers," said Jeff La Rue, company spokesman.

Of Aqua Ohio's nearly 8,100 residential customers in Franklin County, he said approximately 6,800 in Blacklick Estates (Madison and Truro townships), Huber Ridge (Blendon Township) and Lake Darby (Prairie Township) receive both water and sewer service.

The average customer in these areas who uses 4,000 gallons a month will see monthly bills totaling $107 drop by about $14, La Rue said.

About 1,300 customers in Worthington Hills (Perry and Sharon townships) and Timberbrook (Norwich Township) receive only water service, according to company information. La Rue said the average customer's $58 bill there will decrease by about $6.

The savings amount to 11.8% for water use and 16.2% for sewer, he said.

Customers also can expect future bill credits.

"Aqua Ohio will return to customers an additional $2.5 million annually, which reflects the remaining tax savings not currently accounted for in rates, on a going-forward basis, until the commission approves updated rates through a distribution rate case," the PUCO said in a news release.

Those credits are expected to be approximately 6% for both water and wastewater services, La Rue said.

Aqua Ohio serves about 500,000 customers in 19 counties throughout the state.