Softened water is safe to drink for most people, but it does contain added sodium that some households should limit

Water softeners remove minerals like calcium and magnesium by replacing them with sodium. The result is safe to drink — municipal water treatment and the softening process itself do not create toxins or contaminants. However, the sodium content matters for certain people. If you or someone in your household has high blood pressure, heart disease, or kidney problems, or follows a doctor-recommended low-sodium diet, you should talk to your doctor before drinking softened water regularly.

The amount of sodium added depends on how hard your water is. Harder water requires more sodium to soften it. A water softener treating very hard water (over 15 grains per gallon) can add 100 to 200 milligrams of sodium per liter. For comparison, the American Heart Association recommends no more than 2,300 milligrams of sodium per day total from all sources. If you drink several glasses of softened water daily and already consume sodium from food, this adds up.

Key Takeaways

  • Softened water is not contaminated or unsafe in the way untreated water can be, but it contains added sodium that replaces the minerals removed.
  • People with high blood pressure, heart disease, kidney disease, or sodium-restricted diets should consult their doctor before regularly drinking softened water.
  • The sodium content varies based on how hard your original water is — harder water requires more sodium to soften.
  • You can reduce sodium intake from softened water by using a reverse osmosis filter on your drinking water tap or by softening only hot water and leaving cold water unsoftened.

How much sodium ends up in softened water

The sodium level in your softened water depends on your water hardness. Water hardness is measured in grains per gallon (GPG) or parts per million (PPM). Most home water softeners are sized to handle water between 10 and 25 GPG. A softener treating water at 10 GPG adds roughly 50 to 100 milligrams of sodium per liter. At 20 GPG, you might see 150 to 200 milligrams per liter.

You can find your water hardness by contacting your local water utility — they publish annual water quality reports that list hardness. If you have a private well, you can order a hardness test kit online or through a local water testing lab for $20 to $50. Once you know your hardness level, your softener installer can tell you the expected sodium content of your softened water.

Who should avoid or limit softened water

People with certain health conditions should be cautious. If you have been diagnosed with high blood pressure, congestive heart failure, kidney disease, or cirrhosis, your doctor may have recommended limiting sodium. Softened water adds sodium on top of what you get from food, so it can make these conditions harder to manage. Infants under one year old should not drink softened water regularly because their kidneys are still developing and cannot handle excess sodium well.

If you are unsure whether softened water is right for you, ask your doctor. They know your health history and can tell you whether the sodium content is a concern. Many people with these conditions can still use a water softener — they just need to take steps to reduce sodium intake from the water itself, which the next section covers.

Ways to reduce sodium if you drink softened water

The simplest option is to install a reverse osmosis (RO) filter on your kitchen sink tap. These filters remove sodium along with other dissolved minerals. They are inexpensive — $150 to $300 for the unit and installation — and produce drinking water with very low sodium. The downside is that RO filters are slow, producing about 5 to 15 gallons per day, so you need to refill a pitcher or wait for water to drip through. They also waste water: for every gallon of filtered water, they send 3 to 5 gallons down the drain.

Another option is to soften only your hot water. You can install a point-of-use softener on just the hot water line coming into your water heater, leaving the cold water tap unsoftened. Cold water from the tap is fine for drinking and cooking in most cases. This approach costs less than a whole-house softener and cuts sodium intake from drinking water to nearly zero, though you still get soft water for showers and laundry.

A third choice is to use bottled water for drinking and cooking if you are on a strict sodium diet. This is more expensive over time but gives you complete control over sodium intake. Some people use a combination: softened water for household use, an RO filter for drinking water, and bottled water as backup.

Softened water and cooking

Using softened water for cooking is generally fine. Softened water actually performs better in some cooking tasks — it dissolves salt and seasonings more evenly, and it produces better results when making pasta or rice because the lack of minerals means less starch buildup. Baking can be slightly affected because calcium in hard water can strengthen gluten, but most home bakers do not notice a difference.

The sodium added during softening is the same concern in cooking as in drinking: if you are on a low-sodium diet, every cup of softened water you use adds a small amount of sodium to your food. If sodium is not a concern for you, softened water is fine for all cooking purposes.

Testing your softened water quality

If you want to know the exact sodium content of your softened water, you can order a water test. A basic test that measures sodium, hardness, and common contaminants costs $25 to $75 and takes one to two weeks. You collect a sample in a sterile bottle provided by the lab, mail it in, and receive a report showing sodium levels in milligrams per liter.

Your water softener should also have a display showing the hardness of the water it is treating and the sodium level it is adding. Check your softener's manual to learn how to read this display. If your softener is not displaying this information, contact the company that installed it — they can run a test and adjust the softener if needed.

Frequently Asked Questions

Can softened water cause high blood pressure?

Softened water alone does not cause high blood pressure in healthy people. However, if you already have high blood pressure and are trying to limit sodium, the added sodium in softened water can make your condition harder to control. Talk to your doctor about whether softened water is right for you.

Is softened water bad for your kidneys?

Softened water is not inherently bad for healthy kidneys. However, if you have kidney disease, your kidneys cannot filter excess sodium as well as they should. In this case, softened water can put extra strain on your kidneys. People with kidney disease should check with their doctor before drinking softened water regularly.

Does boiling softened water remove sodium?

No. Boiling water removes some gases and can kill bacteria, but it does not remove dissolved sodium. If you need to reduce sodium in softened water, boiling will not help. A reverse osmosis filter or point-of-use softener on the cold water line are the effective options.

Can I drink softened water if I have a heart condition?

It depends on your specific condition and your doctor's sodium recommendations. Some heart conditions require strict sodium limits, while others do not. Ask your cardiologist whether the sodium in softened water fits within your diet. Many people with heart conditions can drink softened water if they use an RO filter or soften only hot water.

What if I have very hard water — will the softened water have too much sodium?

Very hard water (over 20 GPG) does require more sodium to soften, which means higher sodium levels in the finished water. If your water is very hard and you are concerned about sodium, a reverse osmosis filter on your drinking tap is the most practical solution. You get soft water for household use and low-sodium water for drinking.