The costs for the Golden State Warriors to build a new arena on the San Francisco waterfront is becoming more expensive than originally estimated, but they continue to push forward.

Even rebuilding the aging piers where the arena will sit is far more expensive than thought at as much as $170 million.

"It's a big number," Joe Lacob said. "But look, we're privately doing this, and we've made the decision we're going to do it. It's more expensive than we thought, but you only live once."

The Warriors hoped to move to San Francisco for the 17-18 season when its lease at Oracle Arena expires.

The project includes an 18,000-seat arena, two parking garages, a hotel, two condominium towers and retail space spread across the 13-acre pier and a 2.3-acre site.

The Warriors were purchased for $450 in November 2010 and was valued at $800 million in August.

Ed Lee, mayor of San Francisco, is confident that the city would not increase its financial exposure.

"I don't think the city can chip in more," Lee said. "I think the numbers are what they are. They rose the last six months. ... We want to support (the Warriors), but we also have limitations on the city. And they know."