How much salt should I put in water to rehydrate?

December 7, 2025 •

3 min read

According to the CDC, proper rehydration can reduce mortality from diarrhea and dehydration by up to 93%, with oral rehydration therapy being a cornerstone of treatment. Adding salt to water helps replenish lost electrolytes, but the correct amount is crucial for effectiveness and safety. Understanding the right balance is key to creating a solution that aids your body's rehydration process without causing harm.

Quick Summary

A small, measured amount of salt in water can aid rehydration by replacing lost sodium and helping the body retain fluid. Over-salting can worsen dehydration and create health risks. The ideal ratio depends on the context, such as illness-related fluid loss versus post-exercise needs.

Key Points

Measurement is Crucial: For general rehydration from sweat loss, use ⅛ to ¼ teaspoon of salt per liter of water. Avoid using arbitrary amounts like a 'pinch'.
Add Sugar for Illness: In cases of severe fluid loss from illness like diarrhea, include 6 teaspoons of sugar along with ½ teaspoon of salt per liter, following WHO guidelines.
Beware of Over-Salting: Too much salt can be harmful, leading to increased blood pressure, kidney strain, and worsening dehydration.
Reserve for Specific Needs: Adding salt to water is not necessary for daily, light hydration. It is most beneficial after intense exercise or during illness-induced fluid loss.
Type of Salt Matters Little: While Himalayan pink salt has trace minerals, table salt is perfectly fine and often easier to measure for an effective rehydration solution.
Consult a Doctor for Severe Cases: If you have severe dehydration or pre-existing conditions, consult a healthcare provider before using homemade solutions.
Monitor Hydration by Urine Color: A light, straw-colored urine indicates proper hydration, while darker urine suggests you need more fluids.

The Science Behind Salt and Rehydration

When you become dehydrated, you lose more than just water; your body also loses essential electrolytes, primarily sodium. Sodium plays a vital role in maintaining fluid balance, nerve function, and muscle contractions. Drinking plain water in large quantities after significant fluid loss can sometimes dilute the body's sodium levels further, a condition called hyponatremia. Adding a small, precise amount of salt to your water helps replace lost sodium, which facilitates better fluid absorption and retention. This is the fundamental principle behind oral rehydration solutions (ORS).

Preparing a Standard Rehydration Solution

For general rehydration due to sweat loss, a simple and safe guideline is to add about ⅛ to ¼ teaspoon of salt per liter of water. This provides approximately 300 to 600 milligrams of sodium, a sufficient amount to aid fluid absorption without overloading the body. This is especially useful for athletes or individuals in hot environments who have experienced significant fluid loss through sweating.

For more severe dehydration, such as from vomiting or diarrhea, a more specific World Health Organization (WHO) formula is recommended, which includes both salt and sugar. The sugar (glucose) is crucial as it helps the intestines absorb sodium and water more efficiently.

Homemade Oral Rehydration Solution (ORS) Recipe (Based on WHO guidelines)

1 liter of clean, boiled, and cooled water
½ teaspoon of salt
6 teaspoons of sugar

Mix the ingredients until they are completely dissolved. This solution is particularly effective for those recovering from an illness causing severe fluid loss.

Comparison Table: Rehydration Options


Feature	Homemade Salt Water (for exercise)	Homemade ORS (with sugar)	Commercial Sports Drink	Plain Water
Primary Use	Replenishing sweat loss during exercise	Combating severe dehydration from illness	Performance during and after intense workouts	Everyday, light hydration
Key Components	Water, small amount of salt	Water, salt, and sugar	Water, electrolytes, and carbohydrates	Water only
Sodium Content	Moderate (300-600mg per liter)	Moderate to high (as per WHO formula)	Variable, typically higher than simple salt water	None
Glucose Content	None	Crucial for sodium absorption	Variable, often high	None
Risks of Overconsumption	Mildly increased blood pressure, thirst	Nausea, hypernatremia if ratio is wrong	Excessive sugar intake, digestive issues	Hyponatremia (electrolyte dilution) in extreme cases

How to Avoid Over-Salting and Health Risks

Excessive salt consumption can be dangerous, leading to high blood pressure, increased risk of heart disease, and kidney damage over the long term. When preparing a homemade rehydration solution, precision is vital. Use a standard measuring spoon rather than a “pinch” to ensure the correct ratio. Most individuals in the developed world already consume too much sodium in their daily diets, so adding salt to water should be reserved for specific situations involving significant fluid loss. If you have pre-existing health conditions like high blood pressure, consult a healthcare provider before increasing your sodium intake. For most people engaging in light to moderate activity, plain water is sufficient for hydration.

Understanding Different Salt Types

While table salt is sufficient for rehydration, some people prefer alternatives like Himalayan pink salt or sea salt, often citing their trace mineral content. While these salts do contain trace minerals, the amount is often negligible and does not provide a significant advantage over standard table salt for basic rehydration. The most critical factor is the amount of sodium, not the salt type. Table salt is also finely ground, making it easier to dissolve and measure accurately.

Conclusion

Properly adding a measured amount of salt to water can be an effective way to rehydrate, particularly after intense exercise or during illness causing fluid loss. For everyday rehydration, plain water is usually best. When a sports drink or medical-grade ORS is necessary, a homemade solution can be prepared by carefully following specific recipes involving both salt and sugar. Always prioritize proper measurement and be mindful of your overall sodium intake to avoid potential health risks. In cases of severe dehydration, especially in children and the elderly, commercial ORS or medical consultation is the safest route. Remember that the goal is not to consume more salt, but to restore the body's natural balance of water and electrolytes, and precision is paramount in achieving this.

World Health Organization information on oral rehydration therapy

Frequently Asked Questions

A simple and effective recipe is to dissolve ⅛ to ¼ teaspoon of salt into one liter of clean drinking water. For more severe fluid loss, add 6 teaspoons of sugar to the solution as well.

Yes, standard table salt is perfectly acceptable and is easy to measure accurately. While other salts like Himalayan pink salt contain trace minerals, their contribution is minimal for rehydration purposes compared to their sodium content.

Adding a small amount of salt to water can be beneficial after an intense workout, especially in hot weather, as it helps replace sodium lost through sweat and aids in better fluid absorption.

Using too much salt can increase your blood pressure, put a strain on your kidneys, and potentially worsen dehydration by drawing water out of your cells.

Yes, especially in cases of severe dehydration from illness. The ratio should be carefully controlled using a solution like the WHO formula. In general, for children, it is safer to use a commercial oral rehydration solution designed for their needs.

For routine, daily hydration without significant fluid loss from sweating or illness, plain water is the best choice. Most people get sufficient sodium from their regular diets.

Follow proven recipes, like the WHO's, and measure ingredients precisely using standard kitchen measurements. If the solution tastes unpleasantly salty, the ratio is likely wrong and should be discarded.