NEXUS | Nutrition Knowledge Hub | Water

Water helps your body maintain the right balance of fluids, which keeps cells and organs working properly. Proper functioning and regulation of internal systems in the human body are maintained through a delicate balance of fluids and electrolytes (3). Imbalanced fluids and electrolytes can put individuals at risk for organ system dysfunction (3). Sodium, the body’s most abundant electrolyte, helps regulate water movement in and out of cells (3). When water intake is inadequate, cells can lose water and shrink, which may compromise physiological function. 

Consequently, staying hydrated is essential because water helps your body (4):

• Regulate normal body temperature
• Support urination, bowel movements, and perspiration
• Lubricate and cushion joints
• Protect sensitive tissues, including the spinal cord

Water in common foods
Water can come from more than beverages, as this chart outlines the water content of various foods.

 

 

Water intake comes mostly from beverages and foods (4). Foods with high water content, such as strawberries and squash, can add about 20% of an adult's water intake (8). Daily water needs depend on age, sex, and pregnancy status. The table details recommendations for total water from beverages and total water intake, including all water consumed from beverages, food, and water.

Note: Total water includes all water consumed from beverages, food, and water.
Data source: Institute of Medicine

Although general water intake guidelines can be helpful, individual hydration needs vary based on several factors such as a person's activity level, environmental temperature, and certain medical conditions (15). For a more personalized estimate, online calculators can help determine your recommended water intake. To calculate your Dietary Reference Intake (DRI) based on the USDA guidelines, visit the USDA DRI Calclulator (16).

Dehydration can occur when too little water is consumed. This occurs when the body lacks sufficient fluid that it needs. Causes of dehydration can be due to fluid loss, insufficient fluid intake, or both (17). This can result from vomiting, diarrhea, and excess sweating when exercising or exposure to hot climates (4). Severe dehydration can be life-threatening.

Symptoms of dehydration range from mild to life-threatening, including (17):

•  Muscle cramps
• Thirst
•  Headache
• Dry or sticky mouth
•  Dry, cool skin
•  Dark yellow urine
• Reduced urination
• Seizures
• Permanent brain damage
• Death

Some studies have investigated whether water can support the prevention of diet-related diseases. A meta-analysis of six observational studies of adults assessed water intake and type 2 diabetes risk, finding that greater intake of plain water was related to lower risk of type 2 diabetes (19). However, it is possible that this relationship is driven by individuals drinking water in lieu of sugar-sweetened beverages or other beverages containing calories. 

Alternatively, many people have concerns about drinking public water sources when they’re unsure whether it is safe. Public water sources go through a series of processes to remove germs and chemicals that would pose public health risks (20). To ensure these processes are effective, public water providers monitor water quality and publicly publish their findings determining water safety (10). In the case that public or well water sources are not safe or inaccessible, such as during emergencies or natural disasters, bottled water can be a key resource.

• The United States Environmental Protection Agency details steps to protect your local drinking water.
• The Water Protector Legal Collective is an Indigenous-led nonprofit organization working towards protecting climate justice movements.
• The USDA can identify your specific daily water intake needs.
• The United States Environmental Protection Agency illustrates how different types of water systems work.
• The CDC provides guidelines about testing your well water.

Last Reviewed on: 5/28/2026