It's been tough being a homebuyer on the West Coast. Prices have been surging for years as house hunters fight for the few available listings. Now the tide could be shifting.

As sellers come off the sidelines to lock in gains, they're starting to boost inventory. New data by brokerage Redfin Corp. shows that supply in several U.S. markets is rising in the places that need it the most, like Seattle; Portland, Oregon; and San Jose, California.

The rise in inventory in these West Coast housing markets has slowed the torrid price increases in the region and, in turn, in the U.S. as a whole, where prices grew at their slowest pace since December 2016. The cooling includes the pace of sales as well. While sales increased in June in many of the nation's biggest markets, including Chicago (9.8%), Washington (5.7%) and Houston (2.4%), declines out west were so sharp they dragged the national figure down to a drop of 3.3%.