What’s causing unsafe bacteria levels at Maine beaches?

PORTLAND PRESS HERALD • July 3, 2026

Maine’s clean coastal waters support a $9 billion tourism industry. However, heavy summer rains frequently turn popular beaches into collection points for agricultural runoff, pet waste, and sewage overflows, according to data from Maine Healthy Beaches program. More than 10 beaches in Maine were deemed unsafe for swimming last week due to high bacteria levels. As of Thursday, all of Maine’s monitored saltwater beaches were considered safe for swimming. When it rains, water rushes over the landscape, picking up waste from wildlife and pets, and carrying it through storm drains and rivers into the surf. Aging septic tanks and leaking sewer pipes can also contribute to the contamination. Annual water safety trends are inextricably tied to the weather. Over the last decade, the frequency of Maine swim advisories mirrored rainfall patterns, with more advisories issued during wetter years and fewer during drought years.