Cascade Natural Gas proposes a 6.75 percent increase in natural gas rates KENNEWICK, WASHINGTON – Sep. 29, 2017 – Cascade Natural Gas Corporation (Cascade) filed the following five separate requests with the Washington Utilities and Transportation Commission (WUTC) proposing an overall average 6.75 percent increase for all customer groups with natural gas service, effective November 1, 2017: Purchased Gas Adjustment