From the Jefferson Parish Web site:

As of this morning, Entergy has not restored power to most of Jefferson Parish’s 505 sewerage lift stations which move wastewater from homes and businesses and to the wastewater treatment plants. Residents are cautioned not to flush toilets, wash clothes or dishes, take showers, or allow any water to go down the drains in their homes or businesses. If the system becomes overwhelmed, sewerage wastewater may back up and overflow into homes and businesses.