Three recreational water sites in West Marin are under an advisory to avoid contact with the water. Samples taken on April 8 indicate that bacterial levels at three sites—Chicken Ranch Beach, Shell Beach and Inkwells/Shafter Bridge—exceeded limits for recreational use. Inkwells was first put under advisory after April 1 testing. The County of Marin Environmental Health Services monitories bacterial levels on a weekly basis from April 1 to Oct. 31 every year at 28 common water-recreation areas. When specific areas are under advisory, the county health department posts warning signs at those sites. According to the Environmental Protection Agency, levels for bacteria such as enterococci, which the county is monitoring at these sites, can correlate with the presence of disease-causing bacteria.