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 evaporate back into the atmosphere or eventually reach the oceans. Hydrologists analyze how water influences the surrounding environment and how changes to the environment influence the quality and quantity of water. They 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 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 in order to allow for their water needs.

Most hydrologists specialize in a particular 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. Some groundwater hydrologists focus on water supply and decide the best locations for wells and the amount of water available for pumping. Other groundwater hydrologists focus on the cleanup of groundwater contaminated by spilled chemicals at a factory, an airport, or a gas station. These hydrologists often give advice about the best places to build waste disposal sites to ensure that groundwater is not contaminated.

Surface water hydrologists study water from aboveground sources such as streams, lakes, and snowpacks. 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.

Work done by hydrologists can sometimes include topics typically associated with atmospheric scientists, including meteorologists. Scientists with an education in hydrology and a concentration in 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 6,800 jobs in 2021. The largest employers of hydrologists were as follows:

Federal government, excluding postal service 26%
State government, excluding education and hospitals 22
Management, scientific, and technical consulting services          20
Engineering services 13
Local government, excluding education and hospitals 11

Hydrologists work in offices and in the field. In offices, hydrologists spend much their time using computers to analyze data and model their findings. In the field, hydrologists may have to wade into lakes and streams to collect samples or to read and inspect monitoring equipment. Hydrologists also need to write reports detailing the status of surface water and groundwater 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

Hydrologists typically need a bachelor’s degree for entry-level jobs; however, some employers prefer to hire candidates who have a master’s degree.


Hydrologists typically need a bachelor’s degree in physical science or a related field, such as natural resources. Employers sometimes prefer to hire candidates who have a master’s degree. Hydrologists conducting research or teaching at the postsecondary level typically need a Ph.D.

Few universities offer undergraduate degrees in hydrology; instead, universities may offer hydrology concentrations in their geosciences, engineering, or earth science programs. Coursework requirements may include math, statistics, and life sciences.

Personality and Interests

Hydrologists typically have an interest in the Building and Thinking interest areas, according to the Holland Code framework. The Building interest area indicates a focus on working with tools and machines, and making or fixing practical things. The Thinking interest area indicates a focus on researching, investigating, and increasing the understanding of natural laws.

If you are not sure whether you have a Building or Thinking interest which might fit with a career as a hydrologist, you can take a career test to measure your interests.

Hydrologists should also possess the following specific 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 $84,030 in May 2021. 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 $51,120, and the highest 10 percent earned more than $135,170.

In May 2021, the median annual wages for hydrologists in the top industries in which they worked were as follows:

Management, scientific, and technical consulting services            $99,340
Engineering services 95,770
Federal government, excluding postal service 92,130
Local government, excluding education and hospitals 82,440
State government, excluding education and hospitals 73,300

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 show little or no change from 2021 to 2031.

Despite limited employment growth, about 600 openings for hydrologists are projected each year, on average, over the decade. Most of those openings are expected to result from the need to replace workers who transfer to different occupations or exit the labor force, such as to retire. 


Demand for the services of hydrologists will stem from ongoing human activities such as mining, construction, and hydraulic fracturing. Environmental concerns, especially global climate change that may contribute to flooding and drought, are likely to increase demand for these scientists. Hydrologists will be needed to assess threats to local, state, and national water supplies and to develop comprehensive water management plans. However, the development and use of integrated technology and review systems may limit the need for some hydrologists.

Population expansion into areas that were previously uninhabited also may increase the risk of flooding, and new communities may encounter water availability issues. Although governments value hydrologists' expertise in finding sustainable solutions to managing water resources, budget constraints will limit hiring and impact growth.

For More Information

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

U.S. Geological Survey

For information on federal government requirements for hydrology positions, visit

U.S. Office of Personnel Management

To find job openings for hydrologists in the federal government, visit


For more information about careers in hydrology, visit

American Geophysical Union

American Geosciences Institute

American Institute of Hydrology

American Water Resources Association

For information from universities about research in the water sciences, visit

Consortium of Universities for the Advancement of Hydrologic Science, INC. (CUAHSI)

For informal education and training in hydrology and other geoscience topics, visit





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