Iowa-American Water customers in the Quad-Cities and Clinton, Iowa, are likely due for small credits in their water bills after the utility and state's consumer advocate's office reached an agreement on a requested rate increase.

In May, Iowa-American had asked for an overall permanent rate increase of 34.8 percent, according to the Iowa Utilities Board, which announced the settlement Friday.

The board gave the company a temporary 26 percent rate increase in July, but because the final agreement allowed less than that, the utility will have to file a refund plan within 30 days.

State regulators said a small credit in customer bills will likely be the result.

State law also requires that interest be applied to the refunds.

It isn't clear how much the credit will be. An Iowa-American representative couldn't be immediately reached Friday afternoon.

Even with the settlement, however, Iowa-American's rates will have risen substantially since before the request.

The agreement means residential customers in the Quad-Cities will have seen their bills go up 26.6 percent. In Clinton, they'll have gone up 21.9 percent.

The utilities board said the final deal allows Iowa-American a $6.06 million annual revenue increase over previous rates.

That's $3.4 million less than the utility initially sought.

The final revenue figure is $758,000 less than what was allowed by the temporary rate increase, the utilities board said.