What Water is Best for Low Sodium Diets?

October 11, 2025 •

4 min read

According to the World Health Organization (WHO), the sodium level in drinking water is typically less than 20 mg/L, but this can vary significantly by region and source. For individuals on a sodium-restricted diet, understanding what water is best for low sodium intake is crucial for managing conditions like high blood pressure, heart disease, and kidney problems.

Quick Summary

The ideal water for a low sodium diet is purified or distilled, as these processes remove dissolved minerals, including sodium. Municipal tap water is generally low in sodium, but local reports should be checked. Mineral and spring waters vary widely in sodium content, so reading labels is essential.

Key Points

Purified Water: Filtered using reverse osmosis or distillation, purified water offers a very low-to-zero sodium option, ideal for strict diets.
Tap Water Variations: Sodium content in municipal tap water is generally low, but can fluctuate based on location and water source. Check local water quality reports for specifics.
Avoid Softened Water: Traditional water softeners replace hard minerals with sodium, significantly increasing the water's sodium content, making it unsuitable for low-sodium diets.
Read Bottled Water Labels: Sodium levels in mineral and spring bottled waters vary widely; checking the label is essential to ensure a low-sodium choice.
Home Filtration for Control: Installing a reverse osmosis system at home is the most effective way to consistently reduce sodium in your drinking water.
Consult a Doctor: Individuals with certain medical conditions like hypertension or kidney problems should consult a healthcare provider for personalized advice on water intake.

Understanding Sodium in Water

Sodium, a vital electrolyte, is naturally present in all water sources, but the concentration varies depending on the source and purification methods. For most healthy adults, the amount of sodium in drinking water makes up only a small fraction of their overall daily intake. However, for those with health conditions requiring careful sodium monitoring, the type of water they drink can make a difference.

How Water Softeners Affect Sodium Levels

One common household source of increased sodium in water is a traditional ion-exchange water softener. These systems replace hard minerals like calcium and magnesium with sodium ions to prevent scale buildup. Depending on the hardness of your water, this can add a significant amount of sodium, ranging from 20 to over 300 mg/L. Individuals on a sodium-restricted diet should bypass the softener for their drinking water or use a different purification method.

Comparison of Low Sodium Water Options

Choosing the right water involves understanding the key differences between various types. While some sources are naturally low in sodium, others are specially treated to remove it.

Purified Water: A Reliable Low-Sodium Choice

Purified water undergoes processes like reverse osmosis (RO) or distillation to remove impurities, including dissolved solids and salts. This results in water with a very low, or virtually zero, sodium content. Because its mineral content is minimal, some find the taste to be flat or lacking. Popular brands often use purification methods, but it is important to verify the sodium content on the label.

Distilled Water: The Sodium-Free Option

Distilled water is created by boiling water into a vapor and condensing it back into a liquid. This process effectively removes all minerals and sodium, making it a completely sodium-free option. It is commonly used for medical equipment and in laboratories, but it is also safe for drinking, especially for those on very strict low-sodium diets.

Municipal Tap Water

The sodium content in tap water varies by municipality, but most public water systems in the U.S. contain between 5 and 20 mg of sodium per liter, which is very low. The best way to know for sure is to check your local water quality report. For those on moderate sodium restrictions, tap water is often a safe and economical choice.

Bottled Mineral and Spring Water

Not all bottled water is created equal. The sodium content in mineral and spring water depends on its natural source and can vary significantly. Some mineral waters boast a high mineral content, including sodium, as a selling point. For this reason, it is essential to read the nutrition label carefully when choosing bottled water for a low-sodium diet. Some brands, like Aqua Carpatica and Pineo, market themselves as naturally low in sodium.

Comparison Table: Water Types for a Low-Sodium Diet


Water Type	Sodium Content (mg/L)	Pros	Cons	Best For
Purified Water	<1 to 5	Very low sodium, widely available	Can taste flat; minerals removed	Strict low-sodium diets, everyday use
Distilled Water	<1	Absolutely zero sodium, ideal for cooking	Completely devoid of minerals, flat taste	Very strict restrictions, special uses
Tap Water	5 to 20 (U.S. Avg)	Convenient and economical	Sodium content can vary; requires local check	Most low-sodium diets
Natural Spring/Mineral	Varies widely (5 to >30)	Can contain other beneficial minerals	Must check labels carefully; some are high	Those who prefer natural minerals and read labels
Water Softener Treated	High (20 to >300)	Reduces hard minerals	Significantly increases sodium content	Not suitable for low-sodium intake

How to Choose the Best Water for Low Sodium

To make an informed decision, consider these steps:

Read Labels: For bottled water, always check the nutritional label for the sodium (Na) content per liter. Look for brands that are certified 'low sodium' or 'sodium-free'.
Test Your Tap Water: If you rely on tap water and have health concerns, you can get your water tested. If you use a water softener, this is especially important. Contact your local water provider for the annual water quality report.
Consider Home Filtration: For a consistent low-sodium supply, an in-home reverse osmosis system is a highly effective option for removing up to 99% of dissolved solids, including sodium. Other filters, like charcoal filters, do not remove sodium.
Consult a Professional: If you have severe hypertension, heart disease, or kidney problems, consult with your physician or a registered dietitian to determine the best hydration strategy for your specific needs.

The Health Impact of Low Sodium Water

Reducing sodium intake from all sources, including water, is a proactive step toward better health, especially for managing chronic conditions. Studies have linked high sodium intake to increased blood pressure, which is a major risk factor for heart disease and stroke. For individuals with specific medical concerns, choosing water with low sodium content can help them manage their condition more effectively. It supports kidney function by reducing the burden on these organs and can help prevent fluid retention.

Hydration and Overall Wellness

Beyond specific medical conditions, proper hydration with low sodium water can contribute to overall wellness. It helps maintain the body's electrolyte balance, which is crucial for vital functions like digestion, cognitive performance, and regulating body temperature. Furthermore, drinking zero-sodium water helps avoid the bloating effect sometimes associated with high sodium intake, supporting weight management efforts.

Conclusion

For those needing to watch their sodium intake, the best water is purified or distilled water, which offers a minimal or zero-sodium option. Municipal tap water is a viable choice, provided you check local reports and are not on a very strict diet. Conversely, softened water should generally be avoided for drinking, and mineral/spring water labels must be inspected carefully. By making a conscious choice about your water, you can support your health and better manage your low-sodium diet.

For more information on the impact of sodium on health, refer to the New York State Department of Health's guide on Salt and Drinking Water.

Frequently Asked Questions

No, while both are low in sodium, they are not the same. Purified water removes impurities and dissolved solids using methods like reverse osmosis, resulting in very low sodium. Distilled water is created through boiling and condensation, which removes all minerals, including sodium, creating a completely sodium-free option.

No, boiling water does not remove sodium. Sodium is a mineral that remains in the water even after boiling. In fact, as water evaporates during boiling, the concentration of minerals, including sodium, can increase.

If you are on a low-sodium diet, you should not drink water from a traditional ion-exchange water softener. These systems add sodium to the water to remove hardness minerals, which can significantly increase its sodium content.

In the U.S., a bottled water containing less than 5 mg of sodium per serving can be labeled 'sodium-free'. While there is no official standard for 'low sodium' water, many brands with low-sodium content contain less than 20 mg per liter.

For most people, municipal tap water has low sodium content, typically ranging from 5–20 mg/L. However, levels can be higher in some coastal areas or where road salt runoff is an issue. Checking your local water quality report is the most reliable way to find out.

For a consistent supply of very low-sodium water at home, installing a reverse osmosis (RO) filtration system is one of the most effective solutions. You can also use distilled or purified bottled water, but these options can be more expensive long-term.

If purified bottled water is not available, check the labels of other water types carefully. Some spring water brands are naturally low in sodium and will advertise this. If you are not on a very strict diet, typical municipal tap water is also usually a safe bet, provided you have checked your local report.