SANTA CRUZ (CBS SF) — County officials were warning beachgoers not to swim in the water at Cowell Beach due to unsafe levels of E. coli bacteria.

Warning signs have been posted.

The affected area extends from the Santa Cruz Wharf to Dream Inn.

The Santa Cruz County Water Quality Reports says swimmers should avoid body contact with water because E. coli levels exceed state and county standards.

The presence of E. Coli may be the result of fecal contamination from agricultural runoff. Bodily contact can result in skin, ear and eye infections, and gastrointestinal illness.

According to Heal the Bay, a nonprofit that monitors water quality, Cowell is among the dirtiest beaches on the West Coast.