Drip, drip, drip. Another year, another possible water rate hike.

As Austin City Council considers votes on the city budget and tax rate at a special-called meeting on Monday morning, a coalition of protestors, led by the Save Our Springs Alliance, is expected to gather outside the chambers to oppose yet another water rate hike, the eighth in as many years.

The Austin Water utility wants a 6.7 percent increase on water rates, and a 5 percent increase on wastewater, for a boost of $3.50 on the average monthly bill.

Water utility authorities blame the increase, in part, on the new $504 million water treatment plant being out on the northwest end of town on Lake Travis. Water Treatment Plant No. 4 has been vehemently opposed by environmentalists. It would be the first Austin plant to draw from Lake Travis. The plant, which will go online in 2014, will initially process 50 million gallons of water a day.

Constructing another water treatment is the wrong priority, said critics, including the Save Our Springs Alliance and Livable City. More money should be spent replacing aging water lines that burst, instead of a new plant that isn't needed yet.

"They're not fixing what's broken, yet they want to spend hundreds of millions of dollars on a plant we don't need," said Save Our Springs Alliance Director Bill Bunch. "In our view, the priorities are upside down."

The plant proposal passed on a council vote of 4-3, and proponents such as Mayor Lee Leffingwell said it will be cheaper to build the infrastructure now rather than later. Conservation methods simply won't be enough to keep up with growth.

They also said Austin could face a water shortage in a few years without it. But critics point out that thanks to conservation Austiin's water demand has remained the same for a decade, even as the city has grown in population.

"We've been flat for 10 years," said Bunch of demand. "We can keep it flat for another 15 because there's so much water that we're wasting that could be saved for pennies on the dollar to building a new water plant."