Mobile, Alabama sits where the Mobile and Tensaw Rivers meet at the head of Mobile Bay, creating the second-largest river delta in the United States. It’s a stunning ecological setting — and a complicated one for drinking water.
The Mobile Area Water and Sewer System (MAWSS) serves about 200,000 people, drawing water from Big Creek Lake and other surface sources north of the city. The system treats roughly 40 million gallons per day through conventional treatment including coagulation, sedimentation, filtration, and chloramine disinfection.
Hurricane Country Water Challenges
Mobile is one of the wettest cities in America, averaging over 65 inches of rain annually. It’s also squarely in the hurricane belt. Major storms — and the flooding they bring — create acute water quality challenges.
Heavy rainfall events overwhelm the stormwater system, cause turbidity spikes in source water, and can compromise treatment plant operations. Hurricane Sally in 2020 caused extensive flooding in Mobile, and the city has experienced boil water advisories following severe weather events.
Climate change is making this worse. More intense rainfall events, higher storm surge levels, and rising sea levels in Mobile Bay all increase the risk of contamination entering the water supply during extreme weather.
Industrial Corridor
Mobile’s economy has long depended on heavy industry — shipbuilding, paper mills, chemical manufacturing, and petroleum refining. The industrial corridor along the Mobile River and its tributaries has left a significant contamination legacy.
Several Superfund and state cleanup sites are located in the Mobile area. The 35th Avenue Superfund site in north Birmingham (not Mobile — but the Alabama industrial corridor context matters) and sites closer to home include former manufactured gas plants, chemical facilities, and the Brookley Air Force Base property.
The Mobile River watershed drains a vast area of Alabama and Mississippi, collecting agricultural runoff, industrial discharges, and urban stormwater along the way. MAWSS’s source water from Big Creek Lake is somewhat protected by its location, but the broader watershed pressures require robust treatment.
PFAS Contamination
Military installations in the Mobile area — including the former Brookley Air Force Base (now the Mobile Aeroplex at Brookley) and the Coast Guard Aviation Training Center — have histories of AFFF use for firefighting training. PFAS investigation is ongoing at these facilities.
The Alabama Department of Environmental Management has been conducting PFAS monitoring statewide, and some results near Mobile military sites have shown elevated levels in groundwater. For residents on the municipal MAWSS system, the surface water source and treatment processes provide some protection. But private well users in the greater Mobile area should be tested.
Alabama has not yet adopted state-specific PFAS drinking water standards, so the federal EPA MCLs (4 ppt for PFOA, 4 ppt for PFOS) are the governing limits.
Aging Infrastructure and Lead
Mobile’s water distribution system includes pipes dating back to the early 1900s. MAWSS has been working through its lead service line inventory and replacement program. The city switched from free chlorine to chloramine disinfection partly to improve corrosion control and reduce lead leaching in the distribution system.
Lead levels at the 90th percentile have generally stayed below the EPA action level, but individual homes in older neighborhoods — especially in areas like Midtown, Oakleigh, and the Dauphin Street corridor — may have lead connections or interior lead solder.
Water Hardness and Treatment
Mobile’s water is relatively soft compared to many U.S. cities (typically 20-60 mg/L as calcium carbonate), which is good news for appliances and pipes but means less natural mineral buffering. The soft water can be more corrosive to metal pipes, which is one reason corrosion control treatment is important.
MAWSS uses chloramine rather than free chlorine for residual disinfection. Chloramine produces fewer disinfection byproducts than chlorine, but it can affect dialysis patients and aquarium owners. If either applies to you, be aware that standard carbon filters don’t remove chloramine as effectively as they remove chlorine — you need a catalytic carbon or chloramine-specific filter.
What Residents Can Do
- After storms: Follow all boil water advisories. Even after advisories are lifted, consider flushing your system.
- Check your pipes. Ask MAWSS about your service line material. Lead is most common in homes built before 1950.
- Filter your water. A point-of-use filter certified for lead and chloramine removal handles the most common concerns in Mobile’s water.
- Private well owners: Test for bacteria, nitrates, and PFAS. If you’re near the Aeroplex at Brookley or any former military site, PFAS testing is especially important.
- Know your source. MAWSS publishes water quality data annually. Review it.
If you’re concerned about your water quality, a certified water treatment professional can test your water and advise on the best treatment approach for your home.
For more Gulf Coast coverage, see our report on Baton Rouge water quality.
Sources: Mobile Area Water and Sewer System, Alabama DEM, EPA SDWIS, USGS, Mobile County Health Department