Quick answer
Enter your compensated hardness, which is your tested hardness in grains per gallon plus about 4 gpg for each 1 mg/L of iron. Set regeneration for the middle of the night, keep the reserve modest (around 10%), and choose a salt setting near WQA's target of 4,000 grains of hardness per pound of salt. Use a day override only as a backstop, shorter if you have iron. Then check: softened water should test under 1 gpg, and salt use should roughly match your daily grains divided by 4,000.
- Best for
- Owners of metered (demand-initiated) softeners on well water who have a lab result for hardness and iron.
- Wrong fit
- If the softener is fouled with iron or the water has more iron than a softener should take, changing settings will not fix it. Clean the resin or add an iron filter.
- Tradeoff
- Efficient, low-salt settings save salt but give less capacity per regeneration, so the softener regenerates more often.
The settings that matter
Most modern softener valves, whether programmed with buttons or a phone app, ask for the same handful of values. Here is what each one does and what to enter on a well.
| Setting | What it controls | What to enter |
|---|---|---|
| Hardness | How fast the valve counts down capacity | Compensated hardness in gpg |
| Capacity (resin grains) | How many grains before it regenerates | The capacity that matches your salt setting |
| Salt dose or brine refill | How much salt each regeneration uses | Efficient setting, near 4,000 grains per pound |
| Reserve | Capacity held back so you don’t run out before regeneration | Around 10% |
| Regeneration time | When it regenerates | Middle of the night |
| Day override | Maximum days between regenerations | 7 to 14; shorter with iron |
1. Hardness: use compensated hardness
The hardness setting tells the valve how many grains each gallon removes. The Minnesota Department of Health says to set the softener to the hardness of your water supply; a setting that is too high will cost more to operate and waste water. Too low, and hardness breaks through before the softener regenerates.
On a well, the “hardness of your water supply” should include iron. WQA’s term for the adjusted figure is compensated hardness. The common rule of thumb, used by distributors such as Nelsen Corporation, is:
Hardness setting = hardness (gpg) + 4 × iron (mg/L)
Example: 15 gpg (257 mg/L) of hardness and 1 mg/L of iron gives 19 gpg. If your lab reports hardness in mg/L, divide by 17.1 first.
If you have an iron filter ahead of the softener, test the water after the filter and use that iron number, which may be zero.
2. Salt dose: the setting that decides efficiency
Resin capacity rises with salt, but with diminishing returns. ResinTech’s published curve for a standard softening resin shows roughly 20,000 grains per cubic foot at 5 pounds of salt, 27,000 at 10 pounds and 30,000 at 15 pounds. That works out to:
| Salt dose (lb per cu ft) | Grains removed per lb of salt |
|---|---|
| 5 | about 4,000 |
| 10 | about 2,700 |
| 15 | about 2,000 |
WQA defines salt efficiency as grains of hardness removed per pound of salt, and its best-practice booklet recommends setting softeners to remove 4,000 grains per pound while using no more than 5 gallons of water per 1,000 grains. The 2013 NOWRA and WQA septic guidance also says to make sure the salt setting corresponds to the higher efficiency ratings.
How you set salt depends on the valve:
- Some valves ask for pounds of salt per regeneration or per cubic foot. Use the low end.
- Some ask for brine refill time in minutes. The salt dissolved depends on refill time and the valve’s refill flow. SpringWell’s instructions, for example, set 8 minutes for the SS1 and 10 minutes for the SS4. Ask the manufacturer what dose a given refill time delivers before changing it.
The tradeoff: at an efficient dose you get less capacity per regeneration, so the softener regenerates more often. You use less salt in total.
If you switch to potassium chloride. WQA’s best-practice booklet says potassium chloride needs a 13 to 15% higher concentration than sodium chloride to regenerate the resin, and that it forms salt bridges more readily. Ask the manufacturer whether to raise the salt or brine refill setting after switching, check the brine tank for bridging more often, and retest the softened water after the first few regenerations.
3. Capacity and reserve
Metered valves ask for the resin’s capacity in grains. That number should reflect the salt dose you chose, not the largest figure on the box. SpringWell’s instructions enter 32 (for 32,000) on the SS1 and 48 on the SS4. If you lower the salt dose below the level a capacity rating assumes, lower the capacity setting too, or hardness will break through before regeneration. The manufacturer can tell you the pairing.
The reserve holds back part of the capacity so that you do not run out of soft water during the day before the overnight regeneration. SpringWell’s instructions set it to 10%. A very large reserve means regenerating with unused capacity, which wastes salt.
4. Regeneration time
Pick an hour when nobody is using water, because the house gets hard (or no) water during the cycle. SpringWell’s default is 2:00 am, and its instructions note the first regeneration takes about 90 minutes. If you also have an iron filter, stagger the two so they don’t regenerate at the same time.
5. Day override
A day override forces a regeneration after a set number of days even if the meter has not counted down. WQA recommends using calendar overrides only when necessary: vacation homes, long periods of stagnation, or contaminants that could foul the resin if it sits too long. Iron is one of those. SpringWell’s instructions set 14 days. With iron, consider 7.
6. If you have a timer softener
Timer (time-clock) models regenerate on a schedule regardless of use. WQA recommends avoiding them, and the NOWRA and WQA septic guidance suggests replacing them with demand-initiated units. If you keep one, set the days between regenerations from the sizing math in how to size a water softener, and turn it off when the house is empty for long periods.
Check that the settings work
Test the softened water. Use a hardness strip or drop kit at a cold tap that goes through the softener. You want under 1 gpg (17.1 mg/L). Test again the day before a regeneration, when capacity is lowest.
Check salt use against the math. Salt per day is roughly grains per day divided by your efficiency:
- 300 gallons a day × 14 gpg = 4,200 grains a day
- At 4,000 grains per pound: about 1 pound a day, or about 32 pounds a month (less than one 40-pound bag)
- At 2,000 grains per pound: about 2 pounds a day, or roughly one and a half bags a month
If you are using much more salt than this, the salt setting is high, the hardness setting is too high, or water use is higher than you think. A running toilet adds up fast.
Troubleshooting
| Symptom | Likely cause | Fix |
|---|---|---|
| Hard water all the time | Bypass open, out of salt, salt bridge | Close bypass; break up the bridge; refill |
| Hard water near the end of each cycle | Hardness set too low, capacity set too high, reserve too small | Enter compensated hardness; match capacity to salt dose |
| Regenerates every day or two | Hardness set too high, leaks, softener undersized | Check settings; fix leaks; check sizing |
| Orange stains returning | Iron reaching or fouling the resin | Clean resin; consider an iron filter. See cleaning iron from softener resin |
| High salt use | Inefficient salt setting, high hardness setting | Move toward 4,000 grains per pound |
For iron-specific limits and when the softener is the wrong tool, see iron and water softeners. If you are on a septic system, efficient settings matter even more; see softeners and septic systems.
Common questions
What hardness should I set my water softener to?
Your tested hardness in grains per gallon, plus an allowance for iron. A common rule of thumb adds 4 gpg for each 1 mg/L of iron. The Minnesota Department of Health says to set the softener to the hardness of your water supply; setting it too high raises operating costs and wastes water.
What is a good salt setting for a water softener?
WQA recommends settings that remove 4,000 grains of hardness per pound of salt, using no more than 5 gallons of water per 1,000 grains. That is the low-salt end of a resin's capacity curve, typically around 5 to 6 pounds of salt per cubic foot of resin.
How often should my softener regenerate?
A metered softener regenerates when its capacity is used up. For a well-sized unit that is often around once a week. If yours regenerates every day or two, check the hardness setting, the capacity setting and household water use for leaks.
Why is my water still hard after the softener?
Common causes are an empty brine tank or salt bridge, an open bypass valve, a hardness setting below your actual hardness, iron-fouled resin, or a softener too small for the load. Test the softened water and work through the list below.
Should I set the regeneration day override?
Yes, as a backstop. WQA suggests calendar overrides only where needed, including where contaminants could foul resin if it sits too long. SpringWell's instructions set 14 days; with iron, a shorter interval is safer.
Read next
- How to size a water softenerThe method our sizing calculator uses: people times daily water use times compensated hardness, over days between regenerations, with worked examples.
- Iron and water softenersWhat a softener can and can't do with iron: ferrous vs ferric iron, resin fouling, manganese, published limits, and when an iron filter must go first.
- How to clean iron out of softener resinSigns your softener resin is iron-fouled, how resin cleaners and brine tank cleaning work, when resin needs replacing, and how to stop iron coming back.
- Water softeners and septic systemsCan softener brine go into a septic system? What university, EPA and industry-funded studies found, who paid for them, and how to protect your tank.
Sources
- Minnesota Department of Health: Home Water Softening
- WQA: Getting Smart With Softeners
- WQA: Glossary of Terms (salt efficiency, compensated hardness)
- ResinTech CG8 softening resin data sheet (capacity vs salt dose)
- SpringWell: Salt-Based Water Softener installation instructions (SS1/SS4)
- Nelsen Corporation: Softener Sizing (iron x 4 rule)
- NOWRA and WQA: Guidance for Water Softening and Onsite Wastewater Systems