Water Hardness in North Dakota
Across 3 measured cities — with 97 more covered by labeled county-level estimates — North Dakota's median tap water hardness is 133.2 mg/L (7.8 gpg): hard on the USGS scale. Below: every covered city, the state's hardest and softest water, and the geology that explains it.
Data updated September 13, 2026. Sources: utility-reported water quality data and USGS/EPA Water Quality Portal samples.
What it costs to soften North Dakota water
Water softener cost in North Dakota at 7.8 gpg prices the equipment and the installation labour against the plumber wages published for North Dakota, and labels every range as modelled or measured rather than leaving you to guess which it is.
North Dakota · 7.79 grains per gallon
$952–$1,227
installed, midpoint $1,074 — a 24,000-grain unit, the size 4 people at this hardness need.
Salt and drain water over 10 years: $774–$1,426 — the 8,530,050 grains of hardness this household removes, at the national salt price and water rate whose sources are named below. Filter changes and Service contract are omitted rather than assumed.
Sized for 4 people regenerating every 7 days: 16,359 grains of capacity needed, rounded up to the next common residential size. The median of 3 measured North Dakota cities in our hardness dataset. Modelled: the standard build band published for that state at the size this hardness calls for, equipment priced 2026-10-04 against the May 2025 reference period (OEWS M2025). Salt: the median retailer price of 3 retailers, read 2026-10-04, at a declared salt dose per regeneration. Drain water: about 50 gallons per regeneration from a government extension estimate read 2026-10-04, at the 2024 national average water and sewer rate from a government source read 2026-10-04.
Deciding whether it is worth it at all? Start from how much a water softener costs nationally — the same equipment, installation and ten-year ownership breakdown before any state wage adjustment is applied.
North Dakota Cities by Hardness Category
Measured cities only — labeled county estimates never enter the category counts or the median.
| Category | Range | Measured cities | Share |
|---|---|---|---|
| Soft | 0-60 mg/L | 0 | 0.0% |
| Moderately hard | 60-120 mg/L | 1 | 33.3% |
| Hard | 120-180 mg/L | 2 | 66.7% |
| Very hard | >180 mg/L | 0 | 0.0% |
Hardest and Softest Water in North Dakota
Measured values only; labeled county estimates and values under active dispute never rank.
Every Covered City in North Dakota
All 100 covered North Dakota cities, sorted by population served. "County estimate" rows are labeled context values from USGS/EPA Water Quality Portal county sampling — they never enter the median above. City names link to each city's full water quality page.
| City | Hardness (mg/L) | gpg | Category | Data |
|---|---|---|---|---|
| Fargo | 78.7 | 4.6 | Moderately hard | Computed from Ca+Mg |
| Bismarck | 133.2 | 7.8 | Hard | Computed from Ca+Mg |
| Grand Forks | 390.0 | 22.8 | Very hard | County estimate |
| West Fargo | 392.0 | 22.9 | Very hard | County estimate |
| Dickinson | 320.0 | 18.7 | Very hard | County estimate |
| Mandan | 337.0 | 19.7 | Very hard | County estimate |
| Jamestown | 384.0 | 22.5 | Very hard | County estimate |
| Belcourt | 314.5 | 18.4 | Very hard | County estimate |
| Kindred | 392.0 | 22.9 | Very hard | County estimate |
| Thompson | 390.0 | 22.8 | Very hard | County estimate |
| Gilby | 390.0 | 22.8 | Very hard | County estimate |
| Beulah | 234.0 | 13.7 | Very hard | County estimate |
| Grafton | 437.0 | 25.6 | Very hard | County estimate |
| Rugby | 469.0 | 27.4 | Very hard | County estimate |
| Hillsboro | 520.0 | 30.4 | Very hard | County estimate |
| New Town | 362.0 | 21.2 | Very hard | County estimate |
| Casselton | 392.0 | 22.9 | Very hard | County estimate |
| Langdon | 329.0 | 19.2 | Very hard | County estimate |
| Hazen | 234.0 | 13.7 | Very hard | County estimate |
| Bottineau | 417.0 | 24.4 | Very hard | County estimate |
| Tioga | 427.0 | 25.0 | Very hard | County estimate |
| Lisbon | 435.0 | 25.4 | Very hard | County estimate |
| Carrington | 389.0 | 22.8 | Very hard | County estimate |
| Mayville | 520.0 | 30.4 | Very hard | County estimate |
| Oakes | 469.5 | 27.5 | Very hard | County estimate |
| Garrison | 255.0 | 14.9 | Very hard | County estimate |
| Harvey | 376.0 | 22.0 | Very hard | County estimate |
| Horace | 392.0 | 22.9 | Very hard | County estimate |
| Bowman | 445.0 | 26.0 | Very hard | County estimate |
| Crosby | 422.0 | 24.7 | Very hard | County estimate |
| Park River | 437.0 | 25.6 | Very hard | County estimate |
| Ellendale | 469.5 | 27.5 | Very hard | County estimate |
| New Rockford | 412.5 | 24.1 | Very hard | County estimate |
| Surrey | 395.5 | 23.1 | Very hard | County estimate |
| Larimore | 390.0 | 22.8 | Very hard | County estimate |
| Alexander | 224.5 | 13.1 | Very hard | County estimate |
| Mapleton | 392.0 | 22.9 | Very hard | County estimate |
| Cavalier | 340.0 | 19.9 | Very hard | County estimate |
| Rolla | 314.5 | 18.4 | Very hard | County estimate |
| Washburn | 255.0 | 14.9 | Very hard | County estimate |
| Hettinger | 573.0 | 33.5 | Very hard | County estimate |
| Stanley | 362.0 | 21.2 | Very hard | County estimate |
| Cando | 477.0 | 27.9 | Very hard | County estimate |
| Velva | 413.0 | 24.1 | Very hard | County estimate |
| Burlington | 395.5 | 23.1 | Very hard | County estimate |
| Belfield | 232.5 | 13.6 | Very hard | County estimate |
| Ray | 427.0 | 25.0 | Very hard | County estimate |
| Northwood | 390.0 | 22.8 | Very hard | County estimate |
| Glen Ullin | 337.0 | 19.7 | Very hard | County estimate |
| Hatton | 612.0 | 35.8 | Very hard | County estimate |
| Dunseith | 314.5 | 18.4 | Very hard | County estimate |
| Hebron | 337.0 | 19.7 | Very hard | County estimate |
| Harwood | 392.0 | 22.9 | Very hard | County estimate |
| Wilton | 365.0 | 21.4 | Very hard | County estimate |
| Portland | 612.0 | 35.8 | Very hard | County estimate |
| Minto | 437.0 | 25.6 | Very hard | County estimate |
| Pembina | 340.0 | 19.9 | Very hard | County estimate |
| Center | 453.0 | 26.5 | Very hard | County estimate |
| Edgeley | 406.0 | 23.7 | Very hard | County estimate |
| Rolette | 314.5 | 18.4 | Very hard | County estimate |
| Fessenden | 376.0 | 22.0 | Very hard | County estimate |
| Argusville | 392.0 | 22.9 | Very hard | County estimate |
| Leeds | 431.0 | 25.2 | Very hard | County estimate |
| Emerado | 390.0 | 22.8 | Very hard | County estimate |
| Valley City | 394.0 | 23.0 | Very hard | County estimate |
| Maddock | 431.0 | 25.2 | Very hard | County estimate |
| Neche | 340.0 | 19.9 | Very hard | County estimate |
| Stanton | 234.0 | 13.7 | Very hard | County estimate |
| St. John | 314.5 | 18.4 | Very hard | County estimate |
| St. Thomas | 340.0 | 19.9 | Very hard | County estimate |
| Gackle | 349.0 | 20.4 | Very hard | County estimate |
| Zap | 234.0 | 13.7 | Very hard | County estimate |
| Wimbledon | 394.0 | 23.0 | Very hard | County estimate |
| Sanborn | 394.0 | 23.0 | Very hard | County estimate |
| Golden Valley | 234.0 | 13.7 | Very hard | County estimate |
| Arvilla | 390.0 | 22.8 | Very hard | County estimate |
| Litchville | 394.0 | 23.0 | Very hard | County estimate |
| Kensal | 384.0 | 22.5 | Very hard | County estimate |
| Willow City | 417.0 | 24.4 | Very hard | County estimate |
| Wing | 365.0 | 21.4 | Very hard | County estimate |
| Bowdon | 376.0 | 22.0 | Very hard | County estimate |
| Bisbee | 477.0 | 27.9 | Very hard | County estimate |
| Sykeston | 376.0 | 22.0 | Very hard | County estimate |
| Oberon | 431.0 | 25.2 | Very hard | County estimate |
| Rocklake | 477.0 | 27.9 | Very hard | County estimate |
| Mountain | 340.0 | 19.9 | Very hard | County estimate |
| Dodge | 245.0 | 14.3 | Very hard | County estimate |
| Montpelier | 384.0 | 22.5 | Very hard | County estimate |
| Cleveland | 384.0 | 22.5 | Very hard | County estimate |
| Solen | 337.0 | 19.7 | Very hard | County estimate |
| Jud | 406.0 | 23.7 | Very hard | County estimate |
| Cathay | 163.6 | 9.6 | Hard | Computed from Ca+Mg |
| Cooperstown | 381.5 | 22.3 | Very hard | County estimate |
| Finley | 612.0 | 35.8 | Very hard | County estimate |
| Fullerton | 469.5 | 27.5 | Very hard | County estimate |
| Hankinson | 413.5 | 24.2 | Very hard | County estimate |
| Kenmare | 395.5 | 23.1 | Very hard | County estimate |
| Petersburg | 851.0 | 49.8 | Very hard | County estimate |
| Turtle Lake | 255.0 | 14.9 | Very hard | County estimate |
| Walhalla | 340.0 | 19.9 | Very hard | County estimate |
Above 120 mg/L (7 gpg), scale is usually worth treating — see our water softener guide, or size a system with the hardness calculator & converter.
The Geology Behind North Dakota's Water Hardness
North Dakota sits in the Great Plains and interior lowlands region.
The Great Plains and interior lowlands are underlain by carbonate rock, gypsum, and other evaporite deposits, and the semi-arid climate concentrates dissolved minerals rather than flushing them out. Aquifers like the High Plains (Ogallala) yield water the USGS classifies as hard to very hard across most of the region, from the Dakotas down through Texas. Surface-water systems fed by plains rivers carry much of the same mineral load.
Source: USGS - High Plains aquifer
North Dakota Water Hardness FAQ
Does North Dakota have hard water?
Yes — across North Dakota's measured cities, typical tap water is hard. The median is 133.2 mg/L (7.8 gpg) — hard on the USGS scale, where anything above 120 mg/L (7 gpg) counts as hard. 2 of North Dakota's 3 measured cities fall in the hard or very hard bands (67%), so check your own city rather than the state average.
How hard is tap water in North Dakota?
Across the 3 North Dakota cities with measured values in our index, the median hardness is 133.2 mg/L (7.8 gpg) — hard on the USGS scale. Individual cities range from 78.7 to 163.6 mg/L, so check your own city rather than assuming the state number.
Which city in North Dakota has the hardest water?
Cathay has the hardest measured tap water in our North Dakota index at 163.6 mg/L (9.6 gpg) — hard on the USGS scale. Rankings use measured utility values only; labeled county estimates and values under active dispute are excluded.
Do I need a water softener in North Dakota?
2 of North Dakota's 3 measured cities (67%) fall in the hard or very hard bands — above 120 mg/L (7 gpg), the level where most water treatment professionals suggest considering an ion-exchange softener. Hardness varies utility to utility, so look up your own city's value before sizing equipment.
How do I find my city's exact water hardness?
Enter your ZIP code in our free lookup at tapwaterdata.com/zip to see the value we hold for your North Dakota city from utility-reported water quality data, check your water utility's annual Consumer Confidence Report (CCR), or use a home test-strip kit.
Need whole-house or professional water treatment?
For the problems a pitcher or under-sink filter cannot fix — scale, rust and black staining, sulfur smell, well contamination, or test results you cannot explain. Tell us what is happening and we will connect you with a local water-treatment professional.
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