California Water Service Group has announced two executive appointments, with Tamara S. Johnson promoted to Vice President, California Operations, and Gregory D. Shimansky appointed Vice President, Rates and Regulatory Affairs. The promotions were unanimously approved by the company’s Board of Directors and will take effect on 1 July 2026.
Johnson takes on a newly established leadership role created in response to the company’s expansion and the growing operational demands facing water utilities. She most recently served as Director of Field Operations for the Southern California Region and brings four decades of experience in the public water sector. Her career with California Water Service, the group’s largest subsidiary, began in 1985.
Johnson holds a Master of Business Administration from California State University, Monterey Bay, and a Bachelor of Science in Business Administration from the University of La Verne. She also holds California state certifications in water treatment and water distribution.
Commenting on the appointment, Chairman and Chief Executive Officer Martin A. Kropelnicki said: “This new position reflects our company's growth and the increasing complexity of water utility operations. Tammy is not only a water utility operations expert, she's also an accomplished professional with a track record of getting things done. It's truly a pleasure to welcome to the officer team someone who has dedicated her entire career to the company.”
Shimansky, who joined California Water Service Group in 2024, will now oversee rates and regulatory affairs. Before joining the company, he held regulatory leadership positions at Indiana American Water and San Diego Gas & Electric. He earned a Master of Science in Management from Purdue University and a Bachelor of Arts in Economics from the University of California, Los Angeles.
He succeeds Greg A. Milleman, who is retiring after 10 years with the company.
Kropelnicki said: “Greg is results-oriented, and he has done a tremendous job for us thus far. I believe he will be a real asset to the Company as we continue to pursue regulatory mechanisms and rate designs that help keep our rates affordable for customers while allowing us to make the investments in water system infrastructure that help keep our water service safe and reliable.”
