Is softened water safe to drink? Sodium, the kitchen tap and your options

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General information only, not medical advice. If you're on a sodium-restricted diet or have a condition your doctor is managing, ask them about your drinking water.

How much sodium a softener adds

An ion exchange softener removes hardness by trading it for sodium (or potassium, if you fill it with potassium chloride). University of Nebraska–Lincoln Extension puts the rate at about 8 mg/L of sodium for each grain per gallon (gpg) of hardness removed, so water that started at 10 gpg ends up with about 80 mg/L of sodium. That's on top of whatever sodium your water already had.

Using that rule of thumb, here's the rough math. These are estimates from the 8 mg/L rule, not measurements of any particular home:

For scale, UNL notes that one cup of skim milk has about 125 mg of sodium, and the New York State Department of Health says most people get about 3,400 mg a day from food. Don't know your hardness? Check your utility's water quality report or test it at home, and convert units with the hardness numbers page.

What the sodium guidelines mean

There's no federal enforceable limit for sodium in drinking water. EPA's 2003 Drinking Water Advisory on sodium gives two guidance numbers:

• 20 mg/L is EPA's guidance level for people restricted to a very low sodium diet of 500 mg a day. EPA says this value "should not be extrapolated to the entire population."
• 30 to 60 mg/L is EPA's recommendation based on taste. EPA says water in that range is unlikely to taste salty to most people.

The New York State Department of Health also cites 270 mg/L for people on moderately restricted sodium diets. The Michigan Department of Health and Human Services adds that most people won't notice a salty taste until sodium reaches about 200 mg/L.

So softened water from moderately hard water can easily sit above EPA's 20 mg/L figure, which matters for people on a very low sodium diet and much less for everyone else. EPA's advisory also notes that home softeners can push sodium above 300 mg/L in very hard water.

Who should talk to a doctor

The Minnesota Department of Health says that if you or someone in your home has a history of high blood pressure, you should consult a doctor about drinking softened water. New York's health department says sodium in drinking water is a more serious concern for people with high blood pressure or certain heart, kidney or liver diseases. UNL Extension says people on restricted sodium diets should account for the sodium from softened water and talk with their physician.

Minnesota's health department also notes that the calcium and magnesium a softener removes aren't harmful and may be useful dietary sources, so removing them may mean getting more from food.

Ways to cut the sodium at the tap

1. Keep one unsoftened cold tap. UNL and Minnesota's health department both describe running a cold line to the kitchen faucet that bypasses the softener, for drinking and cooking. Virginia Cooperative Extension suggests softening only the water that gets heated if sodium is a concern. Minnesota adds that toilets, hose spigots and other cold taps usually don't need softened water either.
2. Add a reverse osmosis (RO) filter at the kitchen sink. Montana State University Extension says RO at the drinking tap can remove sodium. Michigan's health department says to look for a system certified to NSF/ANSI 58 with a claim to reduce total dissolved solids (TDS), and to follow the manufacturer's maintenance steps so sodium doesn't pass through. Check the specific claims on the product's certification listing.
3. Switch to potassium chloride. Minnesota's health department lists it as a way to reduce the sodium you drink. It costs more and may need a setting change; see our softener salt guide and your softener's manual.
4. Set the hardness correctly. Michigan's health department suggests testing the water before the softener and following the manufacturer's instructions to reduce sodium if needed. Minnesota adds that a hardness setting that's too high wastes salt and water. If your water is still hard after you change it, see softener not working.

Michigan's health department also says boiling won't remove sodium. It just evaporates water and leaves the sodium more concentrated.

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Other things to know before you drink it

• Older plumbing. Minnesota's health department says softened water can corrode pipes, which can contribute to higher lead and copper in drinking water. It also says not to run a softener for the first few weeks in a home with new copper plumbing, so a protective mineral layer can form.
• Utility-softened water. If your water utility already softens the water, Minnesota's health department says you don't need to soften it again, and doing so may cause corrosion issues. Your water quality report will usually say so.
• Well water. If you're on a private well, testing is your job. Michigan's health department suggests asking a certified lab for a test that includes sodium (sometimes called "partial chemistry" or "complete minerals"). A softener isn't a disinfection system, so get the basic safety tests too (see testing options).

Last updated: 2026-10-30