North Marin Water District must pay a $12,000 fine for discharging chlorinated water into its main reservoir last year. The district, which provides water to customers in Novato, Point Reyes Station, Inverness Park and Olema, was recharging Stafford Lake with treated water from the Russian River in early 2021 when, regulators allege, it accidentally allowed water with high residual chlorine levels to flow into the reservoir for up to four consecutive days. Chlorine-treated water is…