Form 4 Filing for Michael S. Mares Jr. - SVP Operations

This filing details two transactions by Michael S. Mares Jr., SVP Operations at CALIFORNIA WATER SERVICE GROUP, on September 4th and 5th, 2026. In both instances, Mr. Mares disposed of Common Stock to cover tax withholding obligations. On September 4th, 69 shares were disposed of at a price of $50.03 per share, leaving a post-transaction balance of 8318.915 shares. On September 5th, an additional 67 shares were disposed of at the same price, resulting in 8251.915 shares remaining. These dispositions relate to the vesting of Restricted Stock Awards granted on March 4, 2025, and June 5, 2024, respectively, as indicated by footnotes F1 and F2.