Hydrologists study how water moves across and through the Earth’s crust. They study how rain, snow, and other forms of precipitation impact river flows or groundwater levels, and how surface water and groundwater evaporates back into the atmosphere or eventually reaches the oceans. Hydrologists analyze how water influences the surrounding environment and how changes to the environment influence the quality and quantity of water. They can use their expertise to solve problems concerning water quality and availability.


Hydrologists typically do the following:

  • Measure the properties of bodies of water, such as volume and stream flow
  • Collect water and soil samples to test for certain properties, such as the pH or pollution levels
  • Analyze data on the environmental impacts of pollution, erosion, drought, and other problems
  • Research ways to minimize the negative impacts of erosion, sedimentation, or pollution on the environment
  • Use computer models to forecast future water supplies, the spread of pollution, floods, and other events
  • Evaluate the feasibility of water-related projects, such as hydroelectric power plants, irrigation systems, and wastewater treatment facilities
  • Prepare written reports and presentations of their findings

Hydrologists may use remote sensing equipment to collect data. They, or technicians whom they supervise, usually install and maintain this equipment. Hydrologists also use sophisticated computer programs to analyze the data collected. Computer models are often developed by hydrologists to help them understand complex datasets. Hydrologists also use geographic information systems (GIS) and global positioning system (GPS) equipment to do their jobs.

Hydrologists work closely with engineers, scientists, and public officials to study and manage the water supply. For example, they work with policymakers to develop water conservation plans and with biologists to monitor wildlife to allow for their water needs.

Most hydrologists specialize in a specific water source or a certain aspect of the water cycle, such as the evaporation of water from lakes and streams. The following are examples of types of hydrologists:

Groundwater hydrologists study the water below the Earth’s surface. Most groundwater hydrologists focus on the cleanup of groundwater contaminated by spilled chemicals at a factory, an airport or a gas station. Some groundwater hydrologists focus on water supply and decide the best locations for wells and the amount of water available for pumping. These hydrologists often give advice about the best places to build waste disposal sites to ensure that the waste does not contaminate the groundwater.

Surface water hydrologists study water from aboveground sources such as streams, lakes, and snow packs. They may predict future water levels by tracking usage and precipitation data to help reservoir managers decide when to release or store water. They also produce flood forecasts and help develop flood management plans.

Scientists with an education in hydrology who concentrate their efforts in the area of water quality are environmental scientists and specialists. Some people with a hydrology background become high school teachers or postsecondary teachers.

Work Environment

Hydrologists held about 7,400 jobs in 2012. The industries that employed the most hydrologists in 2012 were as follows: 

Federal government, excluding postal service 29%
Management, scientific, and technical consulting services 20
Engineering services 18
State government, excluding education and hospitals 17
Local government, excluding education and hospitals 8

Hydrologists work in the field and in offices. In the field, hydrologists may have to wade into lakes and streams to collect samples or to read and inspect monitoring equipment. In the office, hydrologists spend much their time using computers to analyze data and model their findings. Hydrologists also need to write reports detailing the status of surface and ground water in specific regions. Many jobs require significant travel. Jobs in the private sector may require international travel.

Work Schedules

Most hydrologists work full time. However, the length of daily shifts may vary when hydrologists work in the field.

Education and Training

For most jobs, hydrologists need a master’s degree with a focus in the natural sciences. Hydrologists may need a license in some states.


Most hydrologists need a master’s degree, but a bachelor’s degree is adequate for some entry-level positions. Many hydrologists who enter the occupation at the bachelor’s level have an education in a related subject that is not specific to hydrological issues, such as engineering. Applicants for advanced research and university faculty positions typically need a Ph.D.

Few universities offer undergraduate degrees in hydrology; instead, most universities offer hydrology concentrations in their geosciences, engineering, or earth science programs. Students interested in becoming hydrologists need extensive coursework in math, statistics, and physical, computer, and life sciences. Hydrologists may find it helpful to have a background in economics, environmental law, and other government policy related topics. Knowledge of these areas may help hydrologists communicate with and understand the goals of policy makers and other government workers.

Students who have experience with computer modeling, data analysis, and digital mapping will be the most prepared to enter the job market.

Important Qualities

Analytical skills. Hydrologists need to analyze data collected in the field and examine the results of laboratory tests.

Communication skills. Hydrologists prepare detailed reports that document their research methods and findings. They may have to present their findings to people who do not have a technical background, such as government officials or the general public.

Critical-thinking skills. Hydrologists assess the risks posed to the water supply by pollution, floods, droughts, and other threats. They develop water management plans to handle these threats.

Interpersonal skills. Most hydrologists work as part of a diverse team with engineers, technicians, and other scientists.

Physical stamina. When they are in the field, hydrologists may need to hike to remote locations while carrying testing and sampling equipment.


The median annual wage for hydrologists was $75,530 in May 2012. The median wage is the wage at which half the workers in an occupation earned more than that amount and half earned less. The lowest 10 percent earned less than $48,450, and the top 10 percent more than $112,840.

In May 2012, the median annual wages for hydrologists in the top five industries employing hydrologists were as follows:

Federal government, excluding postal service $84,540
Engineering services 80,310
Management, scientific, and technical consulting services 78,580
Local government, excluding education and hospitals 69,000
State government, excluding education and hospitals 63,450

Most hydrologists work full time. However, the length of daily shifts may vary when hydrologists work in the field.

Job Outlook

Employment of hydrologists is projected to grow 10 percent from 2012 to 2022, about as fast as the average for all occupations. Demand for the services of hydrologists will stem from increases in human activities such as mining, construction, and hydraulic fracturing. Environmental concerns, especially global climate change and the possibility of sea level rise in addition to local concerns such as flooding and drought, are likely to increase demand for hydrologists in the future.

Managing the nation’s water resources will be critical as the population grows and increased human activity changes the natural water cycle. Population expansion into areas that were previously uninhabited may increase the risk of flooding, and new communities may encounter water availability issues. These issues will all need the understanding and knowledge that hydrologists have to find sustainable solutions.

More hydrologists will be necessary to assess the threats that global climate change poses to local, state, and national water supplies. For example, changes in climate affect the severity and frequency of droughts and floods. Hydrologists are critical to developing comprehensive water management plans that address these and other problems linked to climate change.

Job Prospects

Hydrologists with computer modeling experience will have the best opportunities in the future.

For More Information

For more information about hydrology and the work of hydrologists in the federal government, visit

United States Geological Survey

For more information about careers in hydrology, visit

American Geosciences Institute

American Geophysical Union

American Institute of Hydrology

American Water Resources Association

Source: Bureau of Labor Statistics, U.S. Department of Labor, 2014–2015 Occupational Outlook Handbook, http://www.bls.gov/ooh.

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