Additional 15 percent rate increases will occur annually on every Jan. 1 through 2017.
The board approved the rates unanimously on Thursday.
Average West Valley Water District customers will see their monthly water bills increase from $59 to $68, said Anthony W. Araiza, general manager.
If the rate hikes go into effect the succeeding years, as authorized, the average monthly bill will soar to $118 on Jan. 1, 2017, Araiza said.
"Nobody likes a rate increase. But we couldn't continue dipping into capital. We have depleted our cash reserves," he said.
The district has lost more than $1 million in fiscal years 2008 and 2009 and more than $2 million in fiscal years 2010 and 2011, records show.
The double whammy of a poor economy - which has virtually ended developer fees - and unreimbursed expenses for infrastructure improvements was blamed.
Some of those expenses are related to more sophisticated water-treatment processes necessitated by perchlorate contamination.
Some of those costs might be reimbursed, Araiza said. It was unclear how much the West Valley Water District might recover from a proposed settlement on the perchlorate pollution, he said.
Earlier this month, the U.S. Environmental Protection Agency announced that nine companies and the Defense Department have agreed to pay about $50 million to clean 160 acres of contaminated water, a milestone in a decades-long pollution case that saw the closure of wells in Rialto and Colton.
The rate increase was subject to a Proposition 218 protest vote, but it received less than 100 ballots against it, Araiza said.
More than 9,000 votes against the increase were needed to block it, he said.
Among those opposed to the rate hikes were Bloomington residents Muriel and Lawrence Gautschi, both 74.
"We live on a fixed income. Things keep going up. Obviously water is something we all need," said Muriel Gautschi.
The West Valley Water District serves customers in parts of Rialto, Colton, a sliver of Fontana south of the 10 Freeway and in county areas.
Under the newly approved water rate hike, water used in December will be charged at the old rate and water used on and after Jan. 1 will be charged at the new rate.
Customers' January bills will break out the water used in December and the water used in January and bill according to the rate in effect at the time of use, Araiza said.
Reach Jim via email, call him at 909-386-3855, or find him on Twitter @JSteinbergsRoad.