The bacteria is back.
The Mississippi Department of Environmental Quality said Thursday tests had again discovered it in two places: Pass Christian East Beach and Gulfport West Beach.
The beaches are still open.
The agency issues water contact advisories out of caution when routine tests find Enterococcus, bacteria that live in the intestinal tracts of some animals. The bacteria is not harmful to humans. But it may indicate bacteria from wastewater treatment plants, septic systems or boat sewage is in the water.
The advisories extend from Espy Avenue to Hayden Avenue in Pass Christian, and from Marie Avenue to Camp Avenue in Gulfport. Advisories issued earlier this year are still in place at Pass Christian Central Beach and Long Beach between Oak Gardens Avenue and Girard Avenue.
Water contact advisories were in place on Thursday, March 20 at four beaches: Pass Christian Central Beach, Pass Christian East Beach, Long Beach and Gulfport West Beach. The Mississippi Department of Environmental Quality regularly tests water across the Mississippi Coast and issues advisories out of caution when it detects increased levels of bacteria.
Bacteria levels are normal at all other beaches across the Coast.
It is unclear what causes each advisory, but they increase in warmer months. They are also common after rain because cracked septic tanks, overflowing manholes and crumbling sewer lines can send untreated wastewater into roadside ditches, where storm water drains wash it into the Mississippi Sound.
The bacteria can also come from wildlife, including bird colonies on piers.
The Department of Environmental Quality says swimming during an advisory may lead to increased risk of illness. The warnings have also long frustrated some beach businesses, who say the water is fine and that the advisories hurt tourism.
Here is the full list of advisories in 2025:
March 13: The state issued an advisory for Bay St. Louis Beach and Pass Christian Central Beach. A day later, it issued an advisory for Biloxi East Central Beach. Mississippi lifted the advisories at Bay St. Louis Beach and Biloxi East Central Beach on March 19.
Feb. 13: Mississippi issued an advisory in Long Beach, Pass Christian Central Beach and Bay St. Louis Beach. The advisories in Pass Christian and Bay St. Louis lifted Feb. 26.
Feb. 6: The Mississippi Department of Environmental Quality issued a water contact advisory at Gulfport West Beach. The advisory lifted Feb. 12. The agency also issued an advisory at Waveland Beach, which lifted Feb. 26.
Jan. 17: The Mississippi Department of Environmental Quality issued an advisory at Front Beach in Ocean Springs. The advisory ended Jan. 29.