The advisories issued Wednesday are for Estral Beach, Woodland Beach, Pointe Aux Peaux and Bolles Harbor. They're based on surface water samples taken Tuesday that showed high E. coli bacteria levels.
The department advises against swimming at the beaches. The advisory is expected to remain in effect until next week's water test results are available.
Three other beach areas in the county passed E. coli tests. The beach water tests are done from mid-May through early September.