By Kevin Hanson-The Courier-Herald

The price tag for improvements to Enumclaw's sewage treatment plant continues to shoot upward.

Already the most expensive public works project in city history, costs for the treatment plant upgrade have climbed by nearly $6 million, according to a report issued to the City Council last week. A memo from Public Works Director Chris Searcy indicated the project will likely check in at close to $28.8 million.

During the past five years, costs have skyrocketed. When city officials first started debating options for cleaning up the sewage output, expansion of the present treatment plant was but one possibility and initially carried an estimated cost of about $8 million, Searcy said. That was in 2001 and, by the time that choice was confirmed, costs had jumped several times. The price tag soon doubled to $16 million and, by the early 2004, edged upward to $18 million.

The last truly detailed cost estimate for the treatment plant came in August 2004, when Searcy warned that total costs would likely climb to $23 million.

&#8220Since that time several aspects of the project have changed while material and construction costs have escalated significantly in the Puget Sound region and across the nation,” Searcy wrote in last week's memo to council members.

In breaking down the total project cost, Searcy compared current estimates with those from 2004. He suggested engineering costs have increased $200,000; land acquisition has gone from $950,000 to $1.175 million; wetlands mitigation has soared from $200,000 to $750,000; and construction management costs have doubled, from $900,000 to $1.85 million.

Construction alone, Searcy reported, has gone from $19.6 million to $23.6 million.

To pay for the project, the city has secured almost $25 million in loans from the state's Public Works Trust Fund. Those are to be repaid at a rate of one-half of 1 percent. The largest other source of money comes from cash reserves of $3.6 million.

To help pay for the sewer plant project, the city last year ramped up sewer rates. Customers were hit with a 27 percent rate increase Jan. 1 of this year, will see another 27 percent increase with the coming of 2007 and a final 27 percent rate hike Jan. 1, 2008.

Kevin Hanson can be reached at khanson@courierherald.com.