Sodium in Drinking Water: Who Should Care About It
Health disclaimer: This page provides general educational information about sodium in drinking water. It is not medical advice. If you are on a sodium-restricted diet or have related health conditions, follow the guidance of your doctor.
Sodium in drinking water is a contaminant that matters a great deal to some people and very little to most. For a healthy person, the sodium in their water is usually a minor footnote in their overall diet. For someone on a strict sodium-restricted diet, it can be a real consideration, and ironically the most common source is often a device they installed to improve their water: the softener. Understanding who needs to care about water sodium, and why, is the key to this one.
Where Sodium Comes From
Sodium reaches tap water by several routes. It can be naturally present in groundwater, particularly in coastal areas where saltwater influences the aquifer or in certain mineral-rich formations, and it can enter water through road salt runoff in areas that salt their roads in winter. These natural and environmental sources vary by location.
But for a great many households, the biggest source of sodium in their water is one they added themselves: a water softener. A softener works by exchanging the calcium and magnesium that cause hard water for sodium, which is how it softens the water. That process inherently adds sodium, and the harder the original water, the more sodium the softener adds to soften it. So a home with very hard water and a softener can have noticeably elevated sodium in its softened water, even if the source water was low in sodium to begin with. Many people are surprised to learn their softener is the reason.
Who Needs to Watch It
For most healthy people, the sodium contributed by drinking water is small compared to the sodium in food, and it is not a significant health concern. The picture changes for people on sodium-restricted diets, often for high blood pressure or certain heart or kidney conditions, for whom every source of sodium counts and the amount from water can become relevant. The EPA provides guidance on sodium in drinking water aimed particularly at these sensitive groups, since it is they who most need the information.
This is why sodium is best understood as a targeted concern. If your doctor has you limiting sodium, the sodium in your water, especially from a softener, is worth knowing about and factoring in. If you are healthy and not restricting sodium, it is generally a minor matter. Either way, this page is general information rather than medical advice, and anyone managing a sodium-restricted diet should follow their doctor’s guidance, which can account for all their sodium sources including water.
Testing and Reducing Sodium
If sodium matters for your health, a water test tells you your level, and it is especially worth checking if you have a softener or naturally high-sodium source water. Our testing guides cover how to get a result, and knowing your number lets you and your doctor factor water into your sodium picture accurately.
Reducing sodium from water has a few good options. Reverse osmosis removes sodium effectively at the point of use, making it a common choice for drinking and cooking water in homes with softeners or high natural sodium. Many households with softeners simply leave a cold tap, usually the kitchen, connected to unsoftened water for drinking and cooking, sidestepping the softener’s added sodium where it matters most. Using potassium chloride in place of sodium in a softener is another route, softening the water without adding sodium, as our guidance on softener alternatives discusses. Standard carbon filters and the softener itself do not remove sodium. The reassuring bottom line is that water sodium is easy to manage once you know whether it matters for you, and for most people it quietly does not.