COOS BAY - Summer usually brings sunshine and more visitors to the South Coast. It also means greater water demands for the Coos Bay-North Bend Water Board's treatment plant.

The 18-year-old facility can treat up to eight million gallons of water a day if it runs at full capacity for all 24 hours. That's what happens during the last two weeks of August. The plant can still meet the needs of thirsty lawns and tourists, but if some equipment failed, water production could fall to six million gallons or less.

That wouldn't be enough to meet the area's needs. And increasing water demands in the area could make eight million gallons insufficient in the future.

So, the Water Board is in the planning stages of a treatment plant upgrade that would increase capacity to 12 million gallons treated a day. To prepare to do that, the Water Board will bump water users' rates by 8 percent. Starting this month, the average in-city water user will see another $2 on the monthly bill.

The agency plans to rework the way water is treated. Once it goes through the treatment plant, it's funneled into a nine million-gallon storage well where it continues to be treated. If the level falls below six million gallons, customers would receive water that might not meet treatment standards, Schab said.

Plans to upgrade the treatment plant have been in the works for several years, said general manager Rob Schab, and a design should be selected by the end of the summer.

The Water Board is looking at several options that would allow all the treatment to take place within the plant, rather than sending it to a storage tank where treatment continues. It's also considering whether to build more treatment basins or build them in such a way that they give water more time to be in contact with treatment chemicals.

The agency also is considering new ways to combat the manganese water-discoloration problems that have plagued the agency since the Pony Creek Reservoir expansion. The Water Board's also exploring the possibility of incorporating a hydro-electric generation facility to help off-set the increase in power use produced by the expansion.

The Water Board sought federal stimulus funding, but didn't get any. Still, the agency has two-thirds of the funding in savings, with the rest coming from the rate increases. This year, the average in-city resident will pay an extra $2 a month, which equates to about an 8 percent increase.

The increase is greater than the average 4 percent bump during Schab's tenure, but he sees it as money well spent.

It will ensure the Water Board has funding in place to begin construction in 2010. The project is expected to take two years.

Even though the plant has never had a failure, it's important to stay ahead of the curve with facility upkeep, Schab said.

Doing the rehabilitation work now avoids having to make emergency repairs or limiting water use if something breaks. It also means water users won't have to worry about paying for the plant for decades.

"It's going to serve the community well for the next quarter century," he said.