NAMPA -- Nampa voters overwhelmingly backed the bond for a major upgrade to the city's wastewater treatment plant Tuesday.

The $165 million bond passed with 87 percent of the vote, with 8,898 voters checking the 'yes' box. Thirteen percent, or 1,361 people, voted against it.

The upgrades - which are required by federal law - would have spelled an increase to Nampa residents' sewer bills whether or not the bond passed.

MORE: Nampa residents to vote on sewer bill increase

Mayor Debbie Kling previously said that with the bond, citizens' sewer bill would rise from about $25 per month to $30. The rates will increase each year until 2025, when residents will pay about $72 per month.

Rejecting the bond would have caused residents' sewer bills to double from 2018 to 2019, rising to an average of $110 by 2025.

Nampa residents will see the increase in their sewer bill in October.