EBMUD treats the wastewater you send down your drains to protect the San Francisco Bay. But when winter storms arrive, water in saturated soil can seep through cracks in aging private and public sewer pipes that lead to our Wastewater Treatment Plant. Average wastewater flows can spike dramatically during heavy rains – from about 50 million gallons to 500 million gallons a day! That can overwhelm our systems and lead to partially untreated sewage spills.