ISWS provides data, tools, publications, and guidance for people working with water, weather, climate, and public health in Illinois.
Data & Maps
Illinois water, climate, and weather data support research, planning, and regional decisions. ISWS provides maps and datasets related to flooding, drought, groundwater, streams, water quality, water use, and more.
Explore ISWS Data & Maps.
Publications
ISWS supplies reports, bulletins, journal articles, and historical documents on Illinois water and climate. These cover topics such as groundwater, water quality, flooding, drought, and weather patterns.
Browse ISWS Publications.
Illinois State Scientists
The Illinois State Climatologist and State Hydrologist share science-based knowledge about weather, climate, and water resources across the state. Learn more about their roles and the work they do to support Illinois residents, communities, and decision-makers.
State Climatologist
The Illinois State Climatologist monitors weather and climate conditions, studies long-term trends, and shares information about events such as drought, heat, and heavy rainfall.
Learn more about the Illinois State Climatologist.
State Hydrologist
The Illinois State Hydrologist helps answer questions about floods, drought, water supply, and water quality across the state.
Learn more about the Illinois State Hydrologist.
Agricultural Calculators
Online tools provided by ISWS help Illinois growers track crop growth, pest development, and soil nitrogen levels. These calculators use weather data to support informed decisions about planting, harvest timing, and pest management.
Use ISWS Agricultural Calculators.
Analytical Services
ISWS laboratories support water research, health, environmental monitoring, and watershed studies through analysis of water and sediment samples. Learn about available services for researchers, agencies, and other project partners.
Explore ISWS Analytical Services.
Water Use Reporting
High-capacity well users in Illinois report annual water withdrawals through the Illinois Water Inventory Program. Find reporting guidance and learn how water use data suports planning for the state’s water supply.
Learn about Water Use Reporting.
Water Wells & Safety
ISWS offers training and guidance to professionals and private well owners seeking to safeguard drinking water, review well records, or enhance their water safety knowledge.
Public Health & Training
ISWS offers courses, tools, and support for professionals working in drinking water, wastewater, public health, and private wells, helping them better serve water systems and communities.
Explore Public Health & Training.
Water Wells
ISWS provides private well owners with information about drinking water safety, testing, maintenance, well records, and groundwater conditions, including online learning, direct assistance, and help locating property records.
Find resources for Water Wells.