Does a water softener add sodium? What it means for Monterey Park water
How much sodium a water softener adds to Monterey Park's 2025 water, what that means in one glass, and simple ways to keep a low-sodium tap at home.
Updated · 3 min read
Bottom line
Short answer: yes. A salt softener adds about 8 mg/L of sodium for each grain of hardness it removes. On Monterey Park's city well water, at 20.8 grains, that is roughly 166 mg/L more, for about 191 in all. One 8-ounce glass would hold about 45 mg, under the 140 mg the FDA allows on a "low sodium" food label. If you are on a strict low-sodium diet, keep one cold kitchen tap unsoftened.
The numbers for your water
Monterey Park's 2025 water report lists two supplies side by side: the city's own wells and water the city buys. It does not say which streets get which, so both are shown.
| What you want to know | City wells | Water the city buys |
|---|---|---|
| Hardness | 356 mg/L (20.8 grains) | 246 mg/L (14.3 grains) |
| Sodium in the water now | 25 mg/L | 24 mg/L |
| Sodium a softener adds | About 166 mg/L | About 114 mg/L |
| Sodium after softening | About 191 mg/L | About 138 mg/L |
| In one 8-ounce glass | About 45 mg | About 33 mg |
| In 2 liters a day | About 380 mg, 17 percent of the 2,300 mg daily limit | About 275 mg, 12 percent |
The softener's sodium comes from the exchange itself. The water gives up calcium and magnesium and picks up sodium in their place. The more hardness it removes, the more sodium it adds.
What you'll notice
- Taste. To avoid taste problems, the EPA recommends staying under 30 to 60 mg/L, a threshold for taste-sensitive people. It says many people cannot detect sodium in that range. The World Health Organization's taste guideline is 200 mg/L, and both softened numbers sit under it.
- Your diet. The FDA says most sodium, over 70 percent, comes from packaged and prepared food. The FDA's Daily Value for sodium is less than 2,300 mg a day.
- A strict limit. The EPA's 20 mg/L figure was written for people limited to 500 mg of sodium a day. Monterey Park's water is already at 24 to 25 mg/L before any softener, so anyone on that limit should ask a doctor about drinking water either way.
What helps
| If you want | What helps | Good to know |
|---|---|---|
| A low-sodium drinking tap | One cold kitchen tap on a line that skips the softener | Both North Dakota State and Nebraska extension guides suggest this |
| No sodium chloride | Potassium chloride in place of salt | It adds potassium instead. NDSU says it costs more and uses about 10 percent more salt to rinse. Ask your doctor |
| Hardness gone with nothing added | Reverse osmosis at the kitchen tap | Nebraska Extension says it removes hardness without adding anything, but it is not used for whole homes |
| Less sodium overall | A softener that is not oversized | The EPA advises against oversizing and says to prefer demand-initiated regeneration |
A softener is still the usual answer for scale on faucets and in water heaters. We size it for your hardness and say where the drinking tap should go. See softener sizing for Monterey Park, the Monterey Park water quality report guide and our water softener service.
When to call
- You want a softener but someone at home is on a low-sodium diet.
- You want one tap to stay unsoftened for drinking.
- You have a softener and want to know how much sodium it adds.
- You are thinking about potassium salt or reverse osmosis.
Monterey Park service for this
Hard water is a fact of life in Monterey Park. For this job, start with our water softener service page, then send us a note or text (310) 628-9399.
Before you call
Does a water softener add sodium?
Yes. A salt softener swaps calcium and magnesium for sodium, about 8 mg/L for each grain of hardness removed, according to North Dakota State and Nebraska extension guides.
How much sodium is in softened Monterey Park water?
About 191 mg/L from the city wells and 138 mg/L from the water the city buys, by our arithmetic from the 2025 report. That includes the 24 to 25 mg/L already in the water.
Is softened water safe to drink?
The EPA says drinking water is not a major source of sodium for most people. People on sodium-sensitive treatment should ask their health care provider about it.
Will softened water taste salty?
Not for most people. The EPA says many cannot detect sodium at 30 to 60 mg/L, and the WHO taste guideline is 200 mg/L. The softened numbers here are 138 and 191.
Can I use potassium instead of salt?
Yes. It adds potassium, not sodium. NDSU says it costs more and uses about 10 percent more salt when rinsing. Ask your doctor first.
How do I keep one tap unsoftened?
Plumb a cold kitchen line so it branches off before the softener. Both extension guides suggest this for drinking and cooking.
Sources and notes
Where the numbers come from
Hardness and sodium come from the City of Monterey Park 2025 Water Quality Report. City wells: hardness 356 mg/L (range 340 to 380), 20.8 grains; sodium 25 ppm (20 to 33). Purchased water: hardness 246 mg/L (91 to 335), 14.3 grains; sodium 24 ppm (20 to 32). The report prints hardness in both units, so we used its grain figures.
How we did the math
North Dakota State and Nebraska extension guides both say a softener adds about 8 mg/L of sodium for every grain per gallon of hardness removed. City wells: 20.8 times 8 is 166, plus 25 is 191. Purchased water: 14.3 times 8 is 114, plus 24 is 138. One 8-ounce glass is about 0.237 liter: 191 times 0.237 is 45 mg, and 138 times 0.237 is 33 mg. Two liters a day is also the tap-water figure the EPA's sodium paper uses.
Guideline numbers
The EPA's 2003 sodium advisory says 20 mg/L is the guidance level for people limited to 500 mg of sodium a day, and not for the general population. It says 30 to 60 mg/L is a taste range, that drinking water does not play a significant role in sodium exposure for most people, and that people treated for sodium-sensitive high blood pressure should talk to their health care provider. The FDA label rule: "low sodium" means 140 mg or less per serving.
What these figures leave out
Sodium varies through the year, and a softener may not remove every grain of hardness. Your own tap could differ from the report's average. A home test is the only way to know your tap.
Cited sources
- City of Monterey Park, 2025 Water Quality Report (PDF)
- North Dakota State University Extension, Water Softening (Ion Exchange)
- University of Nebraska Extension, Drinking Water Treatment: Water Softening (Ion Exchange), G08-1491
- U.S. EPA, Drinking Water Advisory: Consumer Acceptability Advice and Health Effects Analysis on Sodium (2003, PDF)
- U.S. FDA, Sodium in Your Diet
- U.S. EPA WaterSense, Soften Water Without Wasting It (PDF)
- Nebraska Extension, Salt-Free Water 'Softener' Options (G2275, PDF)