Sound Transit has seen costs go way up for a second parking garage in Kent for Sounder train riders.

Sound Transit officials revealed during their latest update to the Kent City Council on Aug. 15 that costs are up to an estimated $65 million for the 500-plus stall facility. During a February report, agency staff still used the estimated cost of $35 million.

“The ST2 plan was closer to $35 million,” Karen Kitsis, project coordinator for Sound Transit’s south corridor, said about the tax package approved by voters in 2008 to fund expansion of the system. “When ST3 was being developed, we looked at other (garage) projects in Puyallup and Sumner, and the number was not likely to stand up, so more money was allocated to the structures than what we saw in February.”

The agency’s board restored funding last year for parking garages in Kent and Auburn. Voters approved additional parking garages for Kent and Auburn in 2008 as part of the ST2 package, when costs were much lower. The board suspended the project in 2010 because of the Great Recession when sales tax revenue for the agency came up shorter than projected.

“After the project was reactivated by the board in 2016, Sound Transit reviewed and adjusted available funding for the project based on the cost of similar projects that have been completed in recent years,” said Sound Transit spokeswoman Rachelle Cunningham in an email. “The recent cost estimates for the project validate the need for the higher funding.”

City and Sound Transit officials are in the process of picking a site for the new garage. Construction on the garage is expected to start in 2021 and be completed in 2023, according to transit documents.

Council President Bill Boyce told the agency he prefers an earlier opening.

“I look at the timeline, we have immediate need for parking,” Boyce said. “It seems like forever before we can park cars.”

Sound Transit staff has heard from Kent and Auburn officials about wanting the garage projects done sooner.

“With the Puyallup and Sumner projects we are looking at a different method that could go faster,” Kitsis said.

When Boyce pressed for a specific timeline about an earlier completion date, Kitsis declined to pick a year.

“Perhaps not as long as we show,” she said of the 2023 estimate.

Commuters now park at the Kent Station garage, 301 Railroad Ave. N., which opened in 2001. The garage and surface lot provide 996 parking spaces but fill up quickly.

Sounder trains carried about 1,900 daily riders in 2016 in Kent. Ridership is projected to go as high as 3,000 daily in 2025. About 51 percent of the riders get to Kent Station by car; 14 percent by transit; 12 percent walk; 9 percent are dropped off; 9 percent by carpool or vanpool; and 4 percent by bicycle.

About 80 percent of the riders live east of the Kent Station; 27 percent are from outside of Kent; and 18 percent are from outside of the Sound Transit district, such as Covington.

The council is expected to pick a preferred site for the garage at its Oct. 17 meeting. That recommendation will go to the Sound Transit board on Nov. 16.

The estimated costs for a garage at the four potential sites range from $65 to $82 million, but the funding available remains at $65 million.

“It is not anticipated that funding would increase, but that the scope of the project would be adjusted to remain within available funds,” Cunningham said. “ST would work with stakeholders and elected officials through the environmental, design and project development process to identify the project scope that would be affordable within the available funding.”

Kent’s four potential sites for a second garage are:

• Site 1: vacant lot north of East James Street

515 stalls, estimated cost $75 million

Cost drivers: pedestrian bridge, right-of-way, anticipated hazardous materials abatement

• Site 2: parking lot west of Sounder platform

Parking stalls: 645 (470 new)

Estimated cost: $72 million

Cost drivers: replacement of existing stalls, substantial right-of-way and business relocation costs

• Site 3: Railroad Avenue, storage building, ST surface lot and several Central Ave properties

Parking stalls: 620 (550 new)

Estimated cost: $65 to $75 million depending how align station

Cost drivers: inefficient layout, construction over roadway, interim parking lot, alley vacation

• Site 4: Kiabara Park

Parking stalls: 535 (495 new)

Estimated cost: $82 million

Cost drivers: extremely constrained site, substantial right-of-way costs, replacement of existing stalls, impacts to the Kent Library site.

Sites 1 to 4 on this map are still under consideration by Sound Transit for a new parking garage.