A nonprofit that rates water quality at West Coast beaches just gave Marin a near-perfect score, based on weekly samples collected seasonally at sites across the county last year. Part of the beach monitoring program, the county’s Environmental Health Services division gathered the data between April and October from 23 spots, including Stinson Beach, Muir Beach, Bolinas Beach, and seven beaches on Tomales Bay. Nineteen locations received A-plus wet-weather ratings and the remaining four were graded A; for the dry summer months, just three were brought down to a B. To put that in perspective, in the wettest months, 28 percent of beaches statewide received D or F grades last year, matching the state’s five-year average. (Northern California generally does better than down south, with just 17 percent failing.) “This year’s report is pretty consistent with years in the past—we generally get a pretty good rating,” Lorene Jackson, the county project manager, said. “We get spikes in poor water quality, but they are brief and sporadic, something that is reflective of our healthy watersheds.” There were 17 sewage spills in Marin in 2017 that reached a body of water—half the number recorded in 2016. Two were considered major, three minor and 12 were less than 1,000 gallons. See the full beach report at HealtheBay.org.