Sodium in New Hampshire well water
In New Hampshire, 37% of 17,415 private wells tested between 2006 and 2020 had sodium above the New Hampshire guidance level (20 mg/L), according to NH DHHS.
Sodium enters wells with road salt and from softeners. EPA's guidance level of 20 mg/L matters for people on sodium-restricted diets; most people are not affected below 250 mg/L.
Check your sodium number
Type the value from your lab report. It is compared to the New Hampshire guidance level and the EPA limit, the same way the full interpretation does it.
Test your New Hampshire well for sodium
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
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Systems that remove sodium
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Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For sodium
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
Rather have it installed and sized for your well? Book a free in-home water test with a licensed local company.
Where to get a well tested for sodium in New Hampshire: certified labs, state programs and prices.
By county, from homeowner tests
Share of private wells above the state guidance level (20 mg/L) in tests homeowners sent to the state lab, 2006 to 2020.
| County | Above state level | Wells tested | Highest |
|---|---|---|---|
| Rockingham | 2,769 | 747 mg/L | |
| Strafford | 472 | 687 mg/L | |
| Hillsborough | 3,286 | 633 mg/L | |
| Belknap | 1,473 | 1,335 mg/L | |
| Merrimack | 4,194 | 2,186 mg/L | |
| Carroll | 1,627 | 699 mg/L | |
| Cheshire | 450 | 550 mg/L | |
| Grafton | 2,110 | 1,106 mg/L | |
| Sullivan | 607 | 478 mg/L | |
| Coos | 427 | 348 mg/L |
Towns with the highest share above the state level
- Greenland, Rockingham County83% of 36 wells
- Stratham, Rockingham County81% of 101 wells
- Plaistow, Rockingham County81% of 253 wells
- Hampton Falls, Rockingham County76% of 33 wells
- Atkinson, Rockingham County75% of 101 wells
- Kingston, Rockingham County75% of 71 wells
- Brentwood, Rockingham County75% of 47 wells
- Rollinsford, Strafford County73% of 37 wells
- Lee, Strafford County73% of 33 wells
- Durham, Strafford County71% of 52 wells
- Bedford, Hillsborough County71% of 606 wells
- Hooksett, Merrimack County70% of 135 wells
- Hampstead, Rockingham County66% of 106 wells
- Salem, Rockingham County64% of 88 wells
- Dover, Strafford County59% of 32 wells
- Pembroke, Merrimack County57% of 96 wells
- Epping, Rockingham County57% of 30 wells
- Londonderry, Rockingham County56% of 333 wells
- Mont Vernon, Hillsborough County56% of 39 wells
- Windham, Rockingham County53% of 453 wells
- Derry, Rockingham County53% of 102 wells
- Newton, Rockingham County50% of 42 wells
- South Hampton, Rockingham County50% of 36 wells
- Pelham, Hillsborough County49% of 124 wells
- Bow, Merrimack County49% of 553 wells
By county, from individual samples
Public monitoring samples against the EPA limit; counties with at least 30 samples.
| County | Above EPA limit | Samples | Detected | Median | Highest |
|---|---|---|---|---|---|
| Rockingham | no limit | 328 | 99% | 16 | 258 mg/L |
| Cheshire | no limit | 67 | 97% | 8 | 76 mg/L |
| Carroll | no limit | 247 | 96% | 9 | 390 mg/L |
| Hillsborough | no limit | 260 | 96% | 12.3 | 540 mg/L |
| Strafford | no limit | 91 | 96% | 11 | 510 mg/L |
| Sullivan | no limit | 39 | 95% | 6.9 | 160 mg/L |
| Merrimack | no limit | 460 | 92% | 9 | 184 mg/L |
| Coos | no limit | 159 | 89% | 5.8 | 300 mg/L |
| Grafton | no limit | 214 | 88% | 7 | 570 mg/L |
| Belknap | no limit | 160 | 87% | 9 | 225 mg/L |
Sources
- NH DHHS WISDOM private well summaries: Town summaries of private well tests run by the New Hampshire Public Health Laboratories, published by NH DHHS through the WISDOM environmental public health tracking portal. Exceedance shares use New Hampshire guidance levels, which are stricter than EPA for arsenic (5 ug/L), manganese (0.3 mg/L), radon (2,000 pCi/L) and sodium (20 mg/L). Statistics for small counts are suppressed (*). Retrieved September 3, 2026.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. sodium counts and shares are listed on each county and town page with their sources.