Climate Risk 2050: Which States Face the Greatest Water & Infrastructure Threats?

Methodology

This climate risk forecast uses a composite scoring model that combines six federal data sources to assess each state's vulnerability across four dimensions. Each dimension is scored 0–100, and the overall risk score is the equal-weighted average of all four.

Data Sources

• NOAA Climate Explorer (CMIP5, RCP 4.5) — Mid-century temperature and precipitation projections from the Coupled Model Intercomparison Project Phase 5 ensemble mean, representing a moderate emissions scenario.
• NOAA Sea Level Rise Technical Report (2022) — State-level sea level rise projections under the intermediate scenario, the most widely cited interagency report produced by NOAA, NASA, EPA, USGS, DoD, and FEMA.
• FEMA National Flood Insurance Program (NFIP) — Historical flood insurance claims, payouts, and flood zone designations for 26,000+ ZIP codes.
• U.S. Census Bureau ACS — Housing unit age distribution, used to assess infrastructure vulnerability (older pipes, electrical systems, HVAC).
• EPA SDWIS — Safe Drinking Water Information System violation rates by state, indicating current water quality stress.
• USDM & USGS — U.S. Drought Monitor historical frequency data and USGS groundwater depletion assessments for aquifer stress.

Risk Dimensions

1. Flood Risk Increase (25% of composite)

Combines FEMA NFIP claims density per ZIP code, percentage of ZIPs in high-risk flood zones (A/V), NOAA sea level rise projections for coastal states, and projected precipitation increases. States like Louisiana, New Jersey, and Florida score highest due to a combination of extensive flood history and significant projected sea level rise (10–18 inches by 2050).

2. Drought Stress (25% of composite)

Incorporates USDM drought frequency, USGS groundwater depletion data, projected precipitation decreases, and temperature increases (which accelerate evapotranspiration). Western states — California, Arizona, Nevada, New Mexico — face the highest drought stress due to declining aquifers and projected precipitation reductions of 5–8%.

3. Infrastructure Age Vulnerability (25% of composite)

Uses Census housing age data to estimate water pipe, electrical, and HVAC system ages. States with high percentages of pre-1970 housing stock face elevated risk because aging infrastructure is less resilient to climate stress: old pipes are more prone to failure during freeze-thaw cycles, and outdated water treatment facilities struggle with changing source water quality. Northeastern states — Rhode Island, Pennsylvania, New York, Connecticut — have the oldest housing stock.

4. Water Quality Degradation (25% of composite)

Projects future water quality stress by combining current EPA violation rates with climate factors: higher temperatures promote bacterial growth and algal blooms, drought reduces dilution capacity in source water, and aging infrastructure leaches contaminants. States with already-high violation rates and significant projected warming face compounding risk.

What Climate Science Projects for 2050

Climate projections used in this forecast are based on the RCP 4.5 scenario from CMIP5 — a moderate pathway where global emissions peak around 2040 and then decline. This is considered a "middle-of-the-road" scenario by climate scientists.

Under RCP 4.5, the contiguous United States is projected to warm by 2.2–5.4°F by mid-century (relative to the 1961–1990 baseline), with northern states warming faster than southern states. Precipitation patterns shift: the Northeast and Midwest get wetter, while the Southwest and Southern Plains get drier.

Sea levels along U.S. coastlines are projected to rise 10–12 inches on average by 2050, with the Gulf Coast experiencing up to 18 inches of rise — as much sea level rise by 2050 as the entire 20th century. This transforms moderate flooding events from once every 2–5 years to multiple events per year.

How Climate Change Threatens Water Infrastructure

The intersection of climate change and aging infrastructure creates a compounding risk that few climate models capture. Consider these factors:

• Pipe stress — Temperature extremes cause thermal expansion and contraction in pipes. Cities with pre-1970 cast iron and galvanized steel pipes face increasing main breaks as temperature swings intensify.
• Treatment challenges — Warmer source water temperatures promote algal blooms (including toxic cyanobacteria) that overwhelm conventional treatment. The 2014 Toledo water crisis demonstrated how warming-driven algal blooms can shut down water supply for 500,000 people.
• Saltwater intrusion — Sea level rise pushes saltwater into coastal aquifers and estuaries, contaminating freshwater supplies. Miami-Dade County, southern New Jersey, and parts of Louisiana are already experiencing this.
• Stormwater overload — More intense precipitation events overwhelm aging combined sewer systems, causing sewage overflows that contaminate drinking water sources.

What Homeowners Can Do

Understanding your area's climate risk profile helps you make informed decisions about your home:

1. Check your home's water quality — enter your ZIP code on ZipCheckup to see current EPA violation data, contaminant levels, and safety scores for your area.
2. Know your flood zone — FEMA flood maps determine insurance requirements. Climate change is expanding flood zones in many areas, so check even if you have not flooded before.
3. Inspect aging systems — homes built before 1970 may need plumbing, electrical, and water heater inspections. Lead service lines, galvanized steel pipes, and outdated HVAC systems are more vulnerable to climate stress.
4. Consider water filtration — as source water quality shifts with climate change, home filtration (reverse osmosis or activated carbon) provides a last line of defense. See our Water Filter Matcher.
5. Monitor drought conditions — if you rely on well water, track local aquifer levels through your state geological survey. Groundwater depletion accelerates during drought.

Limitations

This forecast is designed for general awareness, not site-specific risk assessment. Important caveats:

• State-level scores mask significant within-state variation. Coastal and inland areas of the same state often face very different risk profiles.
• Climate projections carry inherent uncertainty. RCP 4.5 represents a moderate scenario; actual outcomes depend on global emissions trajectories.
• Infrastructure data is based on housing age, which is a proxy. Actual pipe materials, treatment plant capacity, and maintenance history vary widely.
• The model does not account for adaptation measures (levees, seawalls, water treatment upgrades) that states may implement before 2050.