McDowell Northwest, Inc. is a piling contractor at 18901 E Valley Hwy in Kent, Washington. Its website says it has served Northwest builders since 1946, with roots in Seattle construction in the early 1900s, and that it has specialized in piling and deep foundations since the late 1960s.
Services listed are auger cast piling, soldier piling, pipe piling and wood piling, with project pages for a noise wall, a substation and a water plant. A separate brand, McDowell Pile King, is promoted for foundation piling, helical pipe piling and shoring walls. That means helical work appears to run through the Pile King side of the business rather than McDowell Northwest's main service list.
Contractors and developers in the Puget Sound region can call 425-251-8570. Ask whether helical piles are installed by McDowell Northwest or by Pile King, what capacity verification and load testing are offered, and whether the company takes on smaller residential jobs.