Harrison County, Mississippi: drinking water report. Harrison County on the Mississippi Gulf Coast has about 208,000 residents in Gulfport, Biloxi, and…
Harrison County on the Mississippi Gulf Coast has about 208,000 residents in Gulfport, Biloxi, and surrounding communities. Water comes from deep wells in the Miocene aquifer system. Keesler Air Force Base in Biloxi and the Mississippi National Guard facilities in Gulfport both have long operational histories. Hurricane Katrina in 2005 devastated the county's infrastructure, and rebuilding efforts included significant water system upgrades.
Keesler AFB has confirmed PFAS contamination from AFFF firefighting foam. According to the Air Force's 2024 environmental investigation, monitoring wells near the base fire training area show PFOS at 55 ppt – well above the federal MCL. The contamination plume extends into residential areas east of the base along the Back Bay of Biloxi.
The Gulfport-Biloxi International Airport, which also houses Mississippi Air National Guard operations, adds another PFAS source. MDEQ's 2024 investigation found combined PFAS at 19 ppt in monitoring wells between the airport and the Gulf coast. The shallow sandy geology of the coastal zone provides minimal natural filtration between contamination sources and the water table.
Harrison County's deep municipal wells draw from aquifers below the PFAS contamination zone, but private shallow wells in the coastal area face more direct exposure risk. If you are on a private well near either military installation, testing is strongly recommended.
Check your water for data at your address. For PFAS, reverse osmosis provides the highest household removal rates. Our water filter guide covers systems with certified PFAS performance. Pull your detailed report for local data, and visit our Mississippi page for statewide patterns.