The most effective way to remove sodium from well water is reverse osmosis, which filters out 90% to 99% of dissolved sodium at the tap. Other options include distillation and deionization, each with different tradeoffs in cost, output volume, and maintenance. The right choice depends on how much sodium is in your water and whether you need treated water at one faucet or throughout your home.
Why Your Well Water Has Sodium
Sodium gets into well water through two main routes: natural geology and water softeners. Underground rock formations, clay deposits, and ancient seabeds dissolve sodium into groundwater over time. In coastal areas or regions with saltwater intrusion, levels can be especially high. If your well draws from an aquifer near any of these sources, elevated sodium is essentially built into your water supply.
The other common culprit is a water softener. These appliances use ion exchange to swap calcium and magnesium (the minerals that make water “hard”) for sodium. Every grain of hardness removed adds roughly 7.5 mg of sodium per gallon of water. If you have very hard water, a softener can push sodium levels well above 100 mg/L. Many people searching for sodium removal solutions are actually dealing with sodium their own softener introduced.
Test Your Water First
Before investing in any treatment system, get a baseline number. The EPA’s guidance level for sodium in drinking water is 20 mg/L, but that threshold was developed specifically for people restricted to 500 mg of total sodium per day. It’s not a legal limit, and it doesn’t apply to the general population. Still, it’s a useful benchmark: if your water is at or below 20 mg/L, sodium removal is unlikely to make a meaningful health difference for most people.
To get an accurate reading, send a sample to a state-certified laboratory. Your local or state health department can provide a list of certified labs in your area. A standard water chemistry panel that includes sodium typically costs between $30 and $100. Testing for total dissolved solids gives you a broader picture of everything in your water, but a sodium-specific test tells you exactly what you’re dealing with.
If you use a water softener, test the water both before the softener (at the wellhead or a pre-softener tap) and after it. This tells you whether your sodium problem is geological, softener-related, or both, and that distinction matters for choosing the right fix.
Reverse Osmosis: The Most Common Solution
Reverse osmosis (RO) is the go-to method for most homeowners dealing with sodium in well water. It works by pushing water through a semipermeable membrane with pores so small that dissolved sodium ions can’t pass through. A well-maintained RO system removes 90% to 99% of sodium along with most other dissolved contaminants.
Most residential RO systems are point-of-use units installed under the kitchen sink. They include a small storage tank that holds 2 to 3 gallons of treated water, which is plenty for drinking and cooking. The system produces water slowly, typically 50 to 100 gallons per day depending on the model, so it’s not practical for treating every tap in your house. Whole-house RO systems exist but cost significantly more and require professional installation.
An RO system does produce wastewater. For every gallon of purified water, older systems send 3 to 4 gallons down the drain. Newer models with permeate pumps cut that ratio closer to 1:1. The membrane itself generally lasts 2 to 3 years before it needs replacing, though well water with high levels of iron, sediment, or bacteria can shorten that lifespan. Pre-filters (typically a sediment filter and a carbon filter) need changing every 6 to 12 months. Keeping up with those pre-filters protects the membrane and keeps the system running efficiently.
One thing to be aware of: RO removes nearly everything from water, including beneficial minerals like calcium and magnesium. Some systems include a remineralization stage that adds a small amount of these back in. The treated water also tastes noticeably different from untreated well water, which most people prefer but is worth knowing in advance.
Distillation: Highest Purity, Lowest Output
Distillation removes sodium by boiling water into steam and then condensing it back into liquid, leaving dissolved minerals behind. According to the Connecticut Department of Public Health, distillation normally removes 99.9% of dissolved materials, making it the most thorough removal method available for home use.
The tradeoff is speed. Small countertop distillers produce less than one quart per hour. Larger units manage about half a gallon per hour. That’s enough for drinking water but not for cooking large meals or supplying a household. Distillers also use a meaningful amount of electricity, since they’re essentially boiling water continuously. Running a countertop unit to produce a gallon of water typically costs a few cents in electricity, but it adds up if you’re distilling several gallons daily.
Distillation makes the most sense if your sodium levels are extremely high, you want the purest possible water, and you only need a few gallons a day. It requires minimal maintenance compared to membrane-based systems: periodic cleaning of the boiling chamber to remove mineral scale is the main task.
Switching Your Softener to Potassium
If your sodium problem comes from a water softener rather than your well itself, the simplest fix may be switching from sodium chloride pellets to potassium chloride pellets. The softener works exactly the same way, exchanging hardness minerals through ion exchange, but it releases potassium into the water instead of sodium. No equipment changes are needed.
Potassium chloride pellets cost roughly two to three times more than sodium chloride, so your ongoing softener costs will increase. Some people also install an under-sink RO system just for the kitchen tap, keeping the sodium-based softener for the rest of the house and filtering out the added sodium only where they drink. This combination approach is popular because it solves the hardness problem throughout the plumbing while keeping drinking water low in sodium.
Deionization: Effective but Less Practical
Deionization systems work similarly to softeners, filtering water through a resin, but they use acids and bases rather than salt to regenerate. This process strips out virtually all dissolved ions, including sodium. The result is very pure water.
For most homeowners, deionization is harder to justify. The regeneration chemicals are hazardous and require careful handling and disposal. Some systems use disposable or exchange-service tanks, where a company swaps your depleted tank for a fresh one on a regular schedule. This avoids the chemical handling but adds recurring cost. Deionization is more commonly used in laboratories and industrial settings than in residential applications, but it is an option if reverse osmosis or distillation won’t work for your situation.
Why Sodium Levels Matter for Health
For healthy adults, the sodium in well water is usually a small fraction of total daily intake. Most dietary sodium comes from food, not water. But for people managing high blood pressure, heart failure, or kidney disease, every source adds up.
A study published in The Lancet Global Health found that for every 100 mg/L decrease in drinking water sodium, blood pressure dropped by an average of about 1 mmHg systolic, and the odds of hypertension fell by 16%. That’s a modest effect from water alone, but it’s clinically meaningful when combined with dietary changes. People in the highest sodium water group had systolic blood pressure readings 7 to 9 points higher than those drinking the lowest-sodium water, even after accounting for diet and lifestyle differences.
If you’re on a sodium-restricted diet of 1,500 to 2,000 mg per day, drinking two liters of water with 200 mg/L of sodium adds 400 mg to your daily intake before you eat anything. At that level, treating your drinking water is a straightforward way to cut a significant chunk of sodium from your day.