How Much Water Should You Drink a Day?

Water is one of the best everyday choices for hydration, but it is not the only way to get fluids. Fruits, vegetables, soups, milk, unsweetened tea and other fluid-containing foods and drinks can also count toward your daily total.

If you have kidney disease, heart disease, diabetes, low sodium, high blood pressure or other conditions that require fluid restrictions, ask your doctor how much fluid is right for you before changing your water or electrolyte routine.

Key takeaways

• Most adults need about 91 to 125 fluid ounces of total water per day from food and beverages.¹

• The “eight glasses a day” rule can be a helpful reminder, but it is not the right target for everyone.

• Water is a strong everyday hydration choice because it has no calories or added sugar.²

• Older adults may need to drink on a schedule instead of waiting to feel thirsty.

• Signs of dehydration can include thirst, dry mouth, dark urine, headache, muscle cramps, fatigue or dizziness.³

• Too much water can also be a concern for some people, especially those with kidney, heart, liver,  sodium or fluid-balance concerns.⁴

• Always consult with your doctor before making major changes to your fluid or electrolyte intake, especially if you take diuretics or manage a chronic condition.

How much water should adults drink? 

Most adults need about 91 to 125 fluid ounces of total water per day from both food and beverages.¹ That total does not have to come from plain water alone.

In general, women tend to need closer to the lower end of this range, while men often need amounts toward the higher end. Your body size, activity level, health conditions, medications and the climate where you live all matter.

How often should you drink water to stay hydrated?

There is no perfect schedule, but many people do better when they spread fluids throughout the day instead of trying to drink a large amount at once.

A simple routine could include drinking fluids:

• When you wake up

• With breakfast, lunch and dinner

• With snacks

• Before and after walking, gardening, exercise or errands

• When taking medications, if your doctor says that is appropriate

• More often during hot weather or after sweating

If you often forget to drink, try placing water where you already spend time: near your bed, favorite chair, desk, kitchen counter, or car cupholder.

What can affect how much water you need?

Your hydration needs can change from day to day. You may need more fluids when you:

• Spend time in hot or humid weather

• Sweat more than usual

• Exercise or spend more time outdoors

• Have a fever

• Have vomiting or diarrhea

• Eat more fiber than usual

• Spend time in dry indoor air

Your needs may also change if you take certain medications or manage a health condition. Kidney disease, heart disease, liver disease, diabetes, low sodium and other conditions requiring fluid restrictions can all affect how much water is right for you. If any of these apply, talk with your doctor before changing your fluid routine.

Why do you need water?

Water helps your body function throughout the day. Getting enough water helps support:

• Body temperature regulation

• Joint cushioning and lubrication

• Digestion and bowel movements

• Waste removal through urine, sweat and stool

• Kidney and urinary tract function

• Clearer thinking and mood

• Healthy routines like walking, gardening, travel and exercise 

Drinking water can also help you replace sugary drinks reducing added sugar and calories while supporting better everyday hydration.²

How hydration needs can change as you age

Staying hydrated can require more effort as you get older. Some older adults may not feel thirsty as quickly. Others may drink less because of appetite changes, mobility challenges, medications, or concerns about frequent bathroom trips.

Small routines can help:

• Keep water near your chair, bed or workspace

• Drink fluids with meals and snacks

• Sip before and after walks or errands

• Add fruit, vegetables, soup or yogurt to meals

• Use a marked bottle or cup to track intake

• Ask your doctor how much fluid is right for your health history 

If you help care for an older adult, watch for changes in energy, confusion, bathroom habits, appetite or fluid intake. These changes can have many causes, so it is best to bring them up with a doctor.

How much water should an older adult drink a day?

Older adults can use the general adult range as a starting point, but the right amount can vary.

A 70-year-old adult, for example, may need more or less depending on:

• Activity level

• Sweating or heat exposure

• Appetite

• Medications

• Kidney function

• Heart health

• Liver health

• Blood pressure

• Sodium levels

• Bladder or mobility concerns 

Older adults should not rely on thirst alone. Drinking smaller amounts throughout the day may be easier than trying to catch up later.

Signs you may not be drinking enough water

Dehydration can happen when your body loses more fluid than it takes in. Common warning signs include:³

• Dry mouth and skin: If your lips feel chapped, your skin lacks its usual elasticity, or your mouth feels sticky, you may be dehydrated.

• Dark-colored urine and infrequent urination: A well-hydrated body produces light yellow or nearly clear urine. If your urine is dark or you’re not using the restroom as often as usual, it’s time to drink more water.

• Fatigue, dizziness, and headaches: Dehydration can lead to low blood volume, making it harder for oxygen and nutrients to reach your brain and muscles. This can leave you feeling sluggish, dizzy, or even lightheaded when you stand up.

• Increased thirst: By the time you feel thirsty, your body is already playing catch-up. If you’re experiencing an unquenchable thirst, it may be a sign you need to rehydrate quickly. However, persistent, unquenchable thirst can also be a symptom of underlying health conditions like diabetes. If this occurs frequently, consult a physician.

Mild dehydration can often be fixed by simply drinking more water, but severe dehydration may require medical attention. If you notice confusion, a rapid heartbeat, lightheadedness, or extreme weakness, seek help immediately.

Best sources of hydration

Good hydration sources include plain water, other unsweetened drinks, and foods with high water content.

These amounts are estimates, not strict targets. Your daily total can come from a mix of beverages and foods. If you have kidney disease, heart disease, liver disease, diabetes, low sodium, high blood pressure or other conditions requiring fluid restrictions, ask your doctor which daily fluid targets are right for you.

Can an older adult drink too much water?

Yes. Drinking too much water can be harmful for some people. Your body normally balances the water you take in with the water you lose. A fluid imbalance can happen if you take in more water than your body can get rid of.⁴

This can be a bigger concern for people with kidney disease, heart conditions, liver disease, low sodium or certain medications. Talk with your doctor if you notice swelling, sudden weight changes, confusion, nausea, weakness or unusual changes in urination.

For most healthy adults, drinking water throughout the day is a good habit. For some people, more is not always better.

Prioritize hydration for better health

Proper hydration is a simple yet powerful way to support your health as you age. From keeping your energy levels up to protecting your joints and kidneys, drinking enough water is essential for overall well-being. Small changes, like carrying a water bottle, eating hydrating foods, and listening to your body’s thirst cues, can make a big difference.

At Mutual of Omaha, we believe in helping you protect what matters most including your health, your future, and your peace of mind. Staying hydrated is just one step toward a healthier lifestyle.

Frequently asked questions (FAQs) about hydration

Can drinking too much water be harmful?

Yes, excessive water intake can lead to a condition called hyponatremia, where sodium levels in the blood become too diluted. This is rare but can be dangerous. The key is balance—drink according to your body’s needs.

Is 64 ounces a good amount of water to drink a day?

For some adults, 64 ounces of plain water may be a reasonable daily goal. But total daily fluid needs are often higher when you include fluids from food and beverages. Most adults need about 91 to 125 fluid ounces of total water per day from food and drinks combined.¹

How much water does a 70-year-old need daily?

A 70-year-old adult can use the general adult range as a starting point: about 91 to 125 fluid ounces of total water per day from foods and beverages.¹ But the right amount depends on health conditions, medications, activity level, climate and whether a doctor has recommended fluid limits.

What are six warning signs you’re not drinking enough water?

Six common signs are thirst, dry or sticky mouth, dark yellow urine, urinating less often, headache and dizziness. Muscle cramps and fatigue can also occur.³ Confusion, fainting, extreme weakness, very little urination or a rapid heartbeat should be treated as more urgent symptoms.

Are sports drinks better than water for hydration?

For everyday hydration, water is best. Sports drinks can be helpful after intense exercise or if you need to replenish electrolytes due to excessive sweating, but they often contain added sugars and should be consumed in moderation.

How often should older adults drink electrolytes?

There is no set schedule that works for everyone. Many healthy adults do not need electrolyte drinks every day. Older adults should ask their doctor whether electrolytes are appropriate and how often to use them, especially if they take diuretics or manage kidney, liver, heart, blood pressure or sodium-related conditions.

Does drinking water lower A1C?

Drinking water alone is not a treatment for lowering A1C. A1C reflects average blood sugar over about three months. Choosing water instead of sugary drinks can support a broader diabetes or prediabetes care plan, but blood sugar goals should always be discussed with your doctor.

Can drinking water lower cortisol levels?

Water is not a proven stand-alone way to lower cortisol. Cortisol is connected to the body’s stress response and can be affected by sleep, illness, medications, and other health factors. If you are concerned about cortisol, stress, sleep, fatigue or mood changes, talk with your doctor.

Sources:

1. MedlinePlus, Water in diet, July 9, 2025, accessed June 2026, medlineplus.gov/ency/article/002471.htm

2. Centers for Disease Control and Prevention, About Water and Healthier Drinks, March 5, 2026, accessed June 2026, cdc.gov/healthy-weight-growth/water-healthy-drinks

3. MedlinePlus, Dehydration, July. 1, 2025, accessed June 2026, medlineplus.gov/ency/article/000982.htm

4. MedlinePlus, Fluid imbalance, Nov. 6, 2025, accessed June 2026, medlineplus.gov/ency/article/001187.htm