Saltwater Intrusion in Coastal Aquifers
As coastal aquifers are over-pumped and seas rise, saltwater pushes inland and contaminates freshwater supplies for cities from Florida to California.
When coastal communities pump groundwater faster than it recharges, the pressure that normally holds back seawater drops, and salt water migrates inland into freshwater aquifers. Rising sea levels accelerate the process.
Florida, coastal California, and the Gulf and Atlantic seaboards are especially exposed. Once an aquifer is contaminated with salt, it can be expensive or impossible to restore, forcing utilities to relocate wells or build desalination and treatment facilities.
Injecting recycled water to create a freshwater barrier — as Orange County and Los Angeles do — is a proven defense, again tying reuse directly to supply protection.
Sources & further reading
States facing this
Delaware
Florida
Louisiana
Maryland
Related analysis
Related issues
Desalination
Desalination offers a drought-proof supply but at high energy cost and with brine-disposal challenges — a complement to, not a replacement for, reuse.
ExploreGroundwater Depletion
Aquifers from the Central Valley to the Ogallala are being pumped faster than they recharge, causing land subsidence and threatening long-term supply.
ExplorePotable Reuse
Advanced purification turns treated wastewater into water that meets or exceeds drinking-water standards — increasingly essential in water-stressed regions.
Explore