How Much Water Should You Drink If You Have Diabetes?

Hydration is important for everyone, but it deserves particular attention if you have diabetes.

High blood glucose levels can cause frequent urination, which may lead to increased fluid loss and dehydration.

How much water should I drink?

There is no single daily fluid target that is appropriate for everyone with diabetes. It depends on your age, size, activity levels, climate, overall health and kidney function. Some people with diabetes will need to increase the amount they drink in hot weather and/or when unwell whilst others may need to reduce their fluid intake (especially those with advanced kidney disease).

Drinking water is a key part of maintaining a healthy lifestyle with diabetes, but drinking more won’t cure your diabetes, replace your medication or guarantee to bring high blood glucose levels back into the correct range.

In this guide you’ll find out why hydration is important, how dehydration can impact blood glucose levels, how much you should be drinking and when to seek medical advice.

Article Index

Why Hydration Matters When You Have Diabetes
How Diabetes Can Lead to Dehydration
How Much Water Should You Drink With Diabetes?
Does Drinking Water Lower Blood Sugar?
Practical Ways to Stay Hydrated
Signs of Dehydration to Watch For
When You May Need to Limit Your Fluid Intake
When Thirst and Frequent Urination Need Medical Attention
Frequently Asked Questions
Key Takeaways

Why Hydration Matters When You Have Diabetes

Water plays a key role in the body. It helps us to regulate our body temperature, carry nutrients around our bodies, keep our circulation working normally, keep our joints lubricated and help us get rid of waste products via urine.

For someone living with diabetes, staying hydrated is really important as high blood glucose levels can cause increased water loss.

If your blood glucose levels stay very high, your kidneys may attempt to remove some of the glucose from your body by passing more glucose in the urine. This will result in you needing to pass more urine which causes excess water loss.

This can cause dehydration.

Dehydration can also make blood glucose management more difficult.

The American Diabetes Association’s 2026 Standards of Care recommend that people with diabetes and those at risk of developing diabetes choose water over other beverages.

Drinking more water isn’t necessarily going to improve your blood glucose levels but making a habit of drinking water can aid hydration and reduce your dependence on sugary drinks.

How Diabetes Can Lead to Dehydration

To understand why dehydration can occur in diabetes, it helps to look at what happens when blood glucose becomes elevated.

When we eat carbohydrate-containing foods, much of the digestible carbohydrate is broken down into glucose. This glucose then enters the bloodstream.

A hormone called insulin is produced by the pancreas which helps glucose enter the cells in the body so that it can be used for energy.

People with diabetes do not produce enough insulin or their body cannot use it properly.

This can cause an increase in glucose in the blood.

If the glucose level becomes high enough the kidneys may start to remove the excess from the blood. The glucose passes out into the urine. As glucose enters the urine, it draws additional water with it, increasing urine production.

This can lead to:

Frequent urination.
Increased thirst.
Loss of body fluids.
Dry mouth.
Dehydration if fluid losses are not adequately replaced.

If you are experiencing these symptoms regularly, make sure you test your blood glucose if you have been advised to do so and talk about the result with your healthcare professional.

How Much Water Should You Drink With Diabetes?

General recommendations for daily water intake exist, but there is no single amount that is appropriate for everyone with diabetes.

Your fluid requirements depend on several factors, including:

Age and body size.
Physical activity and exercise.
Temperature and humidity.
Pregnancy or breastfeeding.
Fever, vomiting, or diarrhoea.
Kidney and heart function.
Medicines that affect fluid balance.

The National Academies’ commonly cited adequate intake estimates for total daily water are approximately 3.7 litres for adult men and 2.7 litres for adult women.

These estimates include water from food and all beverages, not just plain drinking water. They are general population estimates rather than diabetes-specific targets, so they should not be treated as a required daily amount for every person with diabetes.

Many foods such as fruits, vegetables, soups, milk, teas and other drinks can count towards your fluid intake.

If you have a medical condition that affects your body’s ability to regulate fluids, these general estimates may not apply to you.

Should you drink more water because you have diabetes?

Not necessarily.

If your blood glucose levels are frequently high and you are urinating more than usual, you may be losing additional fluids. Replacing those fluids is important, but it is equally important to address the underlying cause of the elevated blood glucose.

Increasing your water intake alone without addressing the ongoing high blood sugar levels would not be a good management strategy.

It would be best to speak to your healthcare professional for personal advice on how much fluid to consume.

Does Drinking Water Lower Blood Sugar?

While drinking enough water is important to stay hydrated, it should not be used as a treatment for raised blood glucose levels.

Drinking water will not wash the insulin out of your system or dilute the glucose in your blood.

It is more complex than that.

Dehydration can make blood glucose management more difficult and may contribute to higher glucose concentrations. Replacing lost fluids helps restore hydration, but drinking water alone is not a reliable treatment for elevated blood glucose.

Water vs. sweet drinks

Drinking water rather than sugar-sweetened drinks can help reduce the amount of extra sugar and carbohydrates you are consuming. This can help you eat a healthier diet and manage your diabetes.

If your blood glucose levels are high, follow your prescribed diabetes-management plan. Do not take additional medication, change your insulin dose, or delay seeking medical advice simply because you are drinking more water. Don’t take any extra medication, adjust your insulin dose or put off seeking medical advice just because you are drinking more water.

Practical Ways to Stay Hydrated

You don’t need to do much to keep on top of your fluid intake.

There are some simple tips to help you keep hydrated.

Drink water regularly

Ensure you have water on hand and take small regular sips throughout the day.

You may need additional fluids during hot weather, exercise, or illness. However, follow any fluid restrictions recommended by your healthcare team.

Choose water instead of sugary beverages

As a general rule, water is a better choice than sugary soft drinks, sweet teas or fruit drinks.

The American Diabetes Association recommends that people with diabetes choose water as their primary beverage.

If you don’t enjoy drinking plain water, you could try:

Lemon or lime water.
Cucumber water.
Unsweetened sparkling water.
Unsweetened tea.
Other suitable sugar-free drinks.

Fruit juice can still contain substantial amounts of naturally occurring sugar and carbohydrates, even when no additional sugar has been added.

Include water-rich foods

Food will also provide you with some water.

Cucumbers, tomatoes and lettuce, as well as watermelon and oranges are all fruits/vegetables that contain high amounts of water.

Eating a variety of these foods can help increase hydration whilst providing important nutrients.

Pay attention during exercise and hot weather

Your fluid needs may increase during exercise or hot weather, particularly if you are sweating heavily. However, follow any fluid restrictions provided by your healthcare professional.

Plan ahead when travelling

Make sure you take some drinking water with you.

It can be easy to forget to stay hydrated in hot weather, on long journeys or when your routine isn’t as usual.

If you have diabetes it makes sense to take your usual supplies for checking your glucose levels and any medication that has been prescribed.

Signs of Dehydration to Watch For

Dehydration can occur if you lose more fluids than you take in.

Common symptoms include:

Increased thirst.
Dry mouth.
Dark yellow urine.
Passing less urine.
Feeling dizzy or lightheaded.
Feeling abnormally tired.
Lack of energy.

These are not specific symptoms. Excessive thirst and passing frequent amounts of urine could be caused by high blood glucose levels.

Urine colour and thirst can provide useful clues about hydration, but neither should be used alone to assess your fluid needs. Medical conditions and certain medications can also affect these signs.

If you have diabetes and notice you are thirsty, passing frequent amounts of urine or feeling fatigued then follow your care plan and check your blood glucose levels. Contact your healthcare professional.

Severe dehydration may require urgent medical treatment. Seek prompt medical attention if you experience confusion, fainting, or an inability to keep fluids down.

When You May Need to Limit Your Fluid Intake

Sometimes people forget that drinking more water may not always be beneficial.

Some people with diabetes may have chronic kidney disease, heart failure or other health issues that mean they have trouble maintaining fluid balance.

If you have significantly reduced kidney function, your body may struggle to remove excess fluid. Drinking too much may lead to swelling, high blood pressure and fluid retention which can impact your breathing and heart.

People receiving dialysis may also need to follow an individualized fluid restriction.

If you have been asked by your healthcare professional to limit fluids then please do so. Don’t try to increase your daily water intake.

Ask your healthcare team how much fluid you should be having per day and if foods such as soups, ices and other foods with liquid in them count towards your total.

When Thirst and Frequent Urination Need Medical Attention

Feeling thirsty from time-to-time is perfectly normal, especially after physical activity or when it is warm.

Continued or abnormal thirst together with passing urine frequently could be a sign that your blood glucose levels are high.

Other symptoms of high blood glucose levels include:

Blurred vision
Increased appetite
Feeling unusually tired
Slow healing of cuts and wounds
Weight loss

Contact your healthcare professional if you experience these symptoms repeatedly, as they may indicate that your blood glucose is not adequately controlled.

Recognizing a possible diabetes emergency

Diabetic ketoacidosis (DKA) is a serious condition that can develop when the body does not have enough insulin. The body begins breaking down fat for energy, causing ketones to build up in the blood.

Symptoms you should look out for include:

Feeling sick or vomiting.
Stomach ache.
Deep or rapid breathing.
Fruity-smelling breath.
Extreme tiredness or weakness.

If you experience symptoms suggesting DKA, seek emergency medical care immediately.

If you become unwell, follow the sick-day plan provided by your healthcare professional. Depending on your diabetes treatment, you may need to monitor your blood glucose more frequently and check your ketone levels.

The CDC advises people with diabetes to drink water during illness to help prevent dehydration. However, symptoms such as difficulty breathing, persistent vomiting, or other warning signs of DKA require urgent medical attention.

Frequently Asked Questions

How much water should a person with type 2 diabetes drink daily?

There is no set amount of water each day that everyone living with type 2 diabetes should drink as individuals will have different needs based on their age, activity levels, climate, overall health and kidney function. General adult water-intake estimates include water from both food and beverages, but they are not specific targets for people with diabetes. Speak with your healthcare professional for a set target.

Can drinking water reduce my blood sugar?

Whilst drinking water can help keep us hydrated it cannot be relied upon to reduce high blood glucose levels. If your glucose is high always follow your diabetes care plan. Speak with a healthcare professional.

Can dehydration cause high blood sugar levels?

Dehydration can make it harder to manage blood glucose and may cause higher levels. High blood glucose can cause more frequent urination which can cause further dehydration.

Is drinking water a better option than juice for someone living with diabetes?

Plain water is generally an excellent choice for hydration because it contains no sugar or carbohydrates. Juice can be high in carbohydrates and may increase your blood glucose. People at risk of hypoglycemia may need a fast-acting source of glucose as part of their prescribed treatment plan.

Can drinking too much water cause problems?

Yes. Drinking excessive amounts of water can cause the sodium in your blood to become diluted. This can cause a dangerous condition known as hyponatraemia. Those with kidney or heart conditions may also suffer from fluid overload if they drink more than what has been recommended by their healthcare team.

Should those with kidney disease caused by diabetes drink more water?

It depends. Some people with chronic kidney disease can have a normal fluid intake however those with severe kidney disease or kidney failure may need to limit their fluid intake. Your kidney function, urine output, dialysis status, and overall health will help determine your appropriate fluid allowance.

Follow the advice of your healthcare team. Speak with a healthcare professional.

Should I drink water before meals to help control my blood sugar?

Drinking water before meals can contribute to your daily fluid intake. However, there is insufficient evidence to recommend a specific amount before every meal as a reliable way to control blood glucose.

Can frequent thirst and urination be a sign of high blood sugar?

Yes. Often those with high blood glucose will experience frequent thirst and urination. If this is happening regularly please check your glucose as advised and speak with a healthcare professional. Drinking more water may not be the solution.

Key Takeaways

It is important to stay hydrated. For those with diabetes, drinking enough fluids is important as you can pass more urine due to having high levels of glucose in the blood.

However, everyone with diabetes won’t need the same amount of water per day. This will depend on your individual situation. Some people with kidney disease or heart failure may need to reduce the amount of fluid they consume.

Here are the main points to remember:

Drink water regularly as part of a healthy daily routine.
Choose water instead of sugar-sweetened beverages whenever practical.
Remember that food and other beverages also contribute to daily water intake.
Do not assume that drinking extra water will lower high blood glucose or treat diabetes.
Pay attention to persistent thirst and frequent urination, as these may indicate elevated blood glucose.
Follow your healthcare professional’s fluid recommendations if you have kidney disease, heart failure, or another condition affecting fluid balance.
Follow your prescribed diabetes-management and sick-day plans when you are unwell.

The goal is not to drink as much water as possible, but to maintain appropriate hydration while managing your blood glucose and following your individual medical needs.

Educational Notice

This article is provided for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment.

Do not change your diabetes medication, insulin dose, or prescribed fluid intake based on this article. Consult a qualified healthcare professional for advice suited to your medical history and individual needs.

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