Public Health Data Sources & Free Tools
Find a useful health signal, check what it measures, and follow it to the original source. Start with our free respiratory dashboard and downloads, or browse the source notes below.
Use or download U.S. respiratory data
Explore national flu-like illness, RSV and COVID-19 surveillance. The CSV and JSON files contain the available national reports shown here, with dates, units and source links.
Flu-like illness measures the percentage of outpatient visits with flu-like symptoms. RSV and COVID-19 measure hospital admissions per 100,000 people. These numbers cannot be compared directly and do not count every infection.
Flu-like illness
Latest source week: Oct 10, 2026
1 available report: Oct 10, 2026 · Trend unavailable; at least three consecutive weekly reports are needed.
Source notesRSV hospital admissions
Latest source week: Oct 10, 2026
2 available weekly reports: Oct 3, 2026–Oct 10, 2026 · Trend unavailable; at least three consecutive weekly reports are needed.
Source notesCOVID-19 hospital admissions
Latest source week: Oct 10, 2026
2 available weekly reports: Oct 3, 2026–Oct 10, 2026 · Trend unavailable; at least three consecutive weekly reports are needed.
Source notes
CDC Use of Agency Materials: CDC public-domain data may be reused under the agency's terms, with source attribution. Third-party materials can have separate restrictions. Original CDC data are available free of charge; their use here does not imply CDC or U.S. government endorsement.Local Health Signal adds activity labels and summaries; these are not CDC classifications.
How To Read This Library
Current signal first
If you want the fastest answer about what is circulating right now, start with the weekly respiratory and outbreak surveillance feeds.
Context second
Annual vaccination and community-health sources add depth, but they should not be confused with real-time outbreak reporting.
Methods are part of trust
Some feeds are here because they explain why sources disagree or how Local Health Signal processes raw public-health data into something usable.
Fast Current-Risk Signals
These are the feeds most useful for answering “what is going around right now?” on the consumer path.
CDC Acute Respiratory Illness Activity by State
Weekly (Fridays)A broad statewide respiratory-illness signal based on emergency department visits.
Source: CDC · Coverage: All 50 states + DC
CDC FluView / ILINet
Weekly (Fridays)Outpatient influenza-like illness surveillance through the ILINet provider network.
Source: CDC Influenza Division · Coverage: National, regional, and participating state ILINet rows, with some current state reporting gaps
CDC NHSN Hospital Respiratory Data
WeeklyHospital admission and capacity data used by Local Health Signal for RSV and COVID-19 state pages.
Source: CDC National Healthcare Safety Network · Coverage: National and state-level hospital reporting
JHU Measles Tracking
WeeklyCumulative county-level measles case rows and source dates compiled from state and local health department reports.
Source: JHU CSSEGISandData Measles Tracking Team · Coverage: Compiled state and county case-report rows
CDC Wastewater Monitoring Program (NWSS)
CDC public dashboards update weekly on Fridays; sampling varies by siteOfficial CDC wastewater monitoring source for community-level viral activity, including COVID-19, influenza A, RSV, measles, A(H5), and monkeypox.
Source: CDC Wastewater Monitoring Program / National Wastewater Surveillance System · Coverage: Municipal wastewater sites across all 50 states, 7 territories, and some tribal communities
Context And Prevention Layers
These sources add local context, vaccination protection, or structural risk, but they are not real-time outbreak trackers.
CDC SchoolVaxView
AnnualKindergarten vaccination coverage rates including MMR, by state.
Source: CDC National Center for Immunization and Respiratory Diseases · Coverage: All 50 states + DC
CDC PLACES: Local Data for Better Health
Annual releaseCity-level chronic disease, prevention, and community health estimates used in Local Health Signal city pages.
Source: CDC · Coverage: City, county, census tract, and place-level estimates
Water Quality And Environmental Health Layers
These sources support the water-quality pages by separating public-water-system reports from address-level and building-level tap questions.
EPA SDWIS: Safe Drinking Water Information System
Federal and state reporting cyclesEPA's federal drinking-water database for public water systems, compliance history, violations, enforcement, and system-level context.
Source: U.S. Environmental Protection Agency · Coverage: U.S. public water systems, violations, enforcement, and system characteristics
EPA Consumer Confidence Reports
Annual reports by July 1Annual Consumer Confidence Reports explain local drinking-water sources, detected regulated contaminants, violations, and required public-water-system context.
Source: U.S. Environmental Protection Agency and local public water systems · Coverage: Community water system annual drinking-water reports
EPA UCMR 5: PFAS and Lithium Monitoring
Multi-year monitoring cycle with periodic data releasesEPA's fifth Unregulated Contaminant Monitoring Rule provides national drinking-water occurrence data for PFAS and lithium from participating public water systems.
Source: U.S. Environmental Protection Agency · Coverage: Selected U.S. public water systems monitoring 29 PFAS and lithium
Comparison And Methods Layer
These sources help explain disagreement between feeds or document the processed layers behind the site.
CDC NSSP Emergency Department Surveillance
WeeklyEmergency department visit data for respiratory illness syndromes.
Source: CDC National Syndromic Surveillance Program · Coverage: Most states (participation varies)
CDC NREVSS Lab Surveillance
WeeklyLaboratory surveillance for respiratory viruses including RSV, influenza, and others.
Source: CDC National Respiratory and Enteric Virus Surveillance System · Coverage: National and regional
PopHIVE Ingest / DataHub
WeeklyProcessed public-health datasets from the PopHIVE project, with source-specific documentation and reuse conditions.
Source: PopHIVE Project · Coverage: National and state-level
Learn more about how we process and combine these sources on ourmethods page.