Critics have said the rate increases are brought on artificially by the annual transfer of millions in utility revenues to the city's General Fund, which pays for public services such as police, libraries and firefighters.
City Council members did not explain their votes from the dais, which came after multiple City Council and commission-level meetings.
The rate hike, which will take effect in December, will translate into an additional $4.66 on each bimonthly bill for the average customer. Above-average users and larger accounts will see higher increases.
During previous hearings, those supporting the rate hike have said they saw no alternative to ensuring that Glendale Water & Power had enough money to operate its water utility.
During the more than four months of discussion on the proposal, officials offered a grim outlook on the utility's finances — detailing significant budget cuts and the delay of critical capital projects.
But at the same time, critics of the proposed increase cited the city's $4-million transfer of water revenues to support the city's General Fund.
The annual transfers, they argued, have added to Glendale Water & Power's financial woes and led to artificially high utility rates.
Utility officials say they have little control over the controversial transfer, which is controlled by the city's Charter and approved each year by the City Council. Critics have in turn called on the council to reduce or abandon the transfer altogether.
"This year's transfer should be reduced to $2.2 million, leaving an addition $2 million for [Glendale Water & Power] to resolve its fiscal problems and to help keep water operations functioning properly," resident Bob Getts said in opposing the proposal at a hearing last week.
The city attorney's office is in the process of evaluating the legality of the money transfer.