Softened water is safe to drink, but most people don't drink it straight from the softener—they drink it from their taps after it has mixed with the rest of your household water.
A water softener removes minerals like calcium and magnesium by swapping them for sodium (salt). The water that comes out of your softener is not harmful to drink. However, the sodium content is the main thing to understand. A typical softened water system adds between 100 and 300 milligrams of sodium per liter, depending on how hard your water is and how your softener is set.
For most people, this amount is not a health concern. The average American gets far more sodium from food than from softened water. But if you have been told by a doctor to limit sodium—because of high blood pressure, heart disease, or kidney problems—you should know how much sodium your softener is adding and talk to your doctor about whether it matters for your situation.
Key Takeaways
- Softened water is safe to drink and does not contain harmful chemicals or byproducts from the softening process itself.
- A water softener adds sodium to your water, typically between 100 and 300 milligrams per liter, which is a small fraction of the sodium most people consume daily from food.
- If you have been advised to follow a low-sodium diet for medical reasons, you should measure your softener's sodium output and discuss it with your doctor.
- Many households install a bypass line so that drinking water and kitchen water come from unsoftened water, while softened water goes to appliances and showers.
- If you are concerned about sodium, a reverse osmosis filter under your kitchen sink can remove sodium from your drinking water without affecting the rest of your softened water system.
Why sodium gets added during softening
A water softener works by running hard water through a tank filled with resin beads. These beads are coated with sodium ions. When hard water passes through, the calcium and magnesium stick to the beads and the sodium is released into the water in their place. This is the only way the softening process works—sodium is not an additive or a byproduct; it is the mechanism itself.
The amount of sodium added depends on how hard your water is. If your water is very hard, the softener has to release more sodium to remove all the minerals. A water test will tell you your water hardness in grains per gallon (GPG) or parts per million (PPM). Your softener's manual or the person who installed it can tell you roughly how much sodium that translates to in your finished water.
Who should be concerned about sodium in softened water
If you have no dietary restrictions on sodium, softened water is not a concern. The sodium in softened water is typically much less than what you get from a single meal. A slice of bread, a serving of cheese, or a can of soup contains far more sodium than a day's worth of softened drinking water.
If you have been told to limit sodium because of high blood pressure, congestive heart failure, kidney disease, or another condition, you should know your softener's sodium output. Some people in this situation choose to install a bypass line so that their kitchen tap and drinking water come from unsoftened water, while the rest of the house gets softened water. Others use a reverse osmosis filter under the kitchen sink, which removes sodium from drinking water only.
Infants under three months old should not regularly drink softened water because their kidneys are still developing and sodium handling is different at that age. If you have a newborn, use unsoftened water for formula and drinking water, or install a bypass line to your kitchen.
How to set up a bypass line for drinking water
A bypass line is a separate pipe that carries unsoftened water directly to your kitchen sink while the rest of your house receives softened water. This is the most common setup in homes where someone has a medical reason to avoid sodium or straightforward prefers the taste of unsoftened water.
If your softener was installed with a bypass line already in place, you may only need to adjust the valves—your installer can show you which ones. If you do not have a bypass line and want one, a plumber can install it. The cost varies, but it is usually a straightforward job that takes a few hours. You will need a separate water line run from your main supply to your kitchen sink, before the water enters the softener.
A bypass line does not require any maintenance beyond what your softener already needs. The unsoftened water going to your kitchen will still be safe to drink if your source water is safe—a bypass line straightforward skips the softening step, it does not filter or treat the water in any other way.
Using a reverse osmosis filter for sodium removal
A reverse osmosis (RO) filter is a small unit that sits under your kitchen sink and filters water at the point of use. It removes sodium, minerals, chlorine, and other dissolved solids by forcing water through a semi-permeable membrane. The result is very pure water with minimal sodium.
An RO filter is less expensive to install than a bypass line—usually between $150 and $400 for the unit and installation—but it has ongoing costs. The filters need to be replaced every 6 to 12 months, and the membrane typically lasts 2 to 3 years. You will also produce some wastewater; most RO systems waste about 3 gallons of water for every 1 gallon of filtered water they produce.
An RO filter works well if you want to reduce sodium in your drinking water only. It does not affect the softened water going to your shower, washing machine, or other appliances. If you are concerned about sodium for medical reasons and want a straightforward, affordable solution, an RO filter under the kitchen sink is often the best choice.
Testing your softened water for sodium
If you want to know exactly how much sodium your softener is adding, you can have your water tested. A basic water test that includes sodium costs between $25 and $75 and can be done by a local water testing lab or sometimes by your water utility.
You can also estimate sodium content using your water hardness and your softener's settings. Most softener manuals include a chart that shows sodium output based on water hardness. If you know your water hardness in GPG and your softener's regeneration cycle, you can look up the approximate sodium level. This is not as precise as a lab test, but it gives you a reasonable idea.
If you have already had your water tested for hardness, you have the information you need to estimate sodium. Write down your hardness number and your softener model number, then contact the manufacturer or your installer—they can tell you the sodium output for your specific setup.
Taste and other reasons people avoid softened drinking water
Some people avoid drinking softened water straightforward because they do not like the taste. Softened water can taste slightly salty or slippery because of the sodium and the absence of minerals. This is purely a preference—there is nothing unsafe about it—but if you notice the taste and it bothers you, a bypass line or an RO filter will solve it.
Others worry about the long-term effects of drinking softened water, even though there is no scientific evidence of harm from the sodium levels in typical household softened water. If you have concerns, talking to your doctor is the best way to settle them. Your doctor knows your health history and can tell you whether softened water is a concern for you specifically.
Frequently Asked Questions
Can I drink water straight from my water softener tank?
Yes, it is safe to drink water directly from the softener tank, but most people do not because it tastes salty and has a slippery feel. The water is not contaminated or harmful—it straightforward has a high sodium content and lacks the minerals that make water taste fresh to most people. If you want to taste it, it is safe, but most households prefer to drink water from their kitchen tap instead.
How much sodium does a water softener add compared to salt in food?
A typical water softener adds 100 to 300 milligrams of sodium per liter. A single slice of bread contains 100 to 200 milligrams of sodium, and a can of soup contains 800 to 1,200 milligrams. Even if you drink a liter of softened water per day, you are getting less sodium from the water than from a single meal. For most people, this is not a meaningful source of dietary sodium.
Do I need a bypass line if I have high blood pressure?
Not necessarily. Whether you need one depends on how much sodium your doctor has told you to limit and how much sodium your softener is adding. Some people with high blood pressure can safely drink softened water; others prefer to avoid it. Talk to your doctor about your softener's sodium output, and they can advise you on whether a bypass line makes sense for your situation.
Will a reverse osmosis filter remove all the sodium from my softened water?
A reverse osmosis filter removes most sodium—typically 90 to 95 percent—along with other dissolved minerals and contaminants. It does not remove 100 percent, but it reduces sodium to levels low enough for most people on sodium-restricted diets. An RO filter is a good middle-ground solution if you want to reduce sodium in your drinking water without installing a full bypass line.
Is softened water safe for babies and young children?
Softened water is not recommended for infants under three months old because their kidneys are still developing and they handle sodium differently than older children and adults. For babies older than three months, softened water is generally safe, but many parents prefer to use unsoftened water or install a bypass line for extra caution. If you have a newborn, ask your pediatrician about your specific situation.