Brightwater estimates inch up to between $1.82 billion to $1.86 billion

The cost of the Brightwater sewage-treatment plant crept further past the $1.8 billion mark — but by a relatively modest amount — in King County's latest update.

Over the past year, the estimated cost has gone up by $16 million, driven by change orders and an expense inadvertently omitted in last year's report.

Brightwater project manager Gunars Sreibers told the Regional Policy Committee last week that $5.7 million of the increase was an expense for electrical equipment at the sewer plant that was left out of last year's cost update. He apologized for the mistake.

The new price doesn't include $152 million in disputed costs related to problems with two machines boring a tunnel that will carry treated wastewater from the new plant near Woodinville to Puget Sound. The plant is scheduled to open in 2011 and the treated-sewage tunnel in 2012.

The damaged machines were idled a year ago as a contractor figured out how to repair them. One machine was restarted earlier this year. The county switched to a different contractor last month to complete the tunnel segment where the second machine remains out of service.

The county and the original contractor, Vinci/Parsons/Frontier-Kemper, disagree over who should pay the $75 million it cost to get Vinci's first machine moving again and who should pay the new contractor, Jay Dee/Coluccio, an estimated $77 million to take over a portion of Vinci's work.

There is no price cap on the Jay Dee/Coluccio contract, which is based on time and materials.

The county Wastewater Treatment Division's new estimate of the Brightwater project cost — incorporating numbers through the end of January — totals $1.82 billion to $1.86 billion. The previous estimate, a year earlier, was $1.8 billion to $1.84 billion.

To finance Brightwater and other sewer-system improvements, County Executive Dow Constantine last month asked the Metropolitan King County Council to raise the monthly wholesale sewer rate per household to $35.15 next year from $31.90. Rates have risen sharply since 2001, when they were $19.75.

With local sewer costs added to the county's wholesale price, customers last year paid an average $48.86 to their city or utility district, according to the county. New sewer customers also pay a monthly capacity charge of $49.07, which Constantine proposes to raise to $50.45 in 2011.

The high Brightwater cost is a sore point for many people. Bellevue City Councilmember Don Davidson said at Wednesday's Regional Policy Committee meeting the cost has more than doubled since the County Council agreed in 1999 to build a third sewage treatment plant. "If we knew it was this expensive, would we have made the same policy decisions?" Davidson said.

Wastewater treatment director Christie True said Friday costs went up substantially when the county decided, in a "fully transparent" process, to build the plant at an inland site that required 13 miles of tunneling. After a "baseline" cost of $1.48 billion was set in 2004, inflation added about $300 million to the price, she said.

Keith Ervin: 206-464-2105 or kervin@seattletimes.com