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US regional hardness research

Highest regional hardness evidence by US city

This comparison starts with the highest qualifying city median rather than a single extreme observation. Every included estimate must meet stricter distance, source-type, site-count, and recency rules.

Complete table

Top 100 qualifying cities

Data through Sep 29, 2026

Highest regional hardness evidence by US city
RankCityMedianClassObserved rangeEvidenceEligible
1FargoND716 PPM41.9 GPGVery Hard716–716 PPM4 ZIPs · 3 sites100%strict rule
2RichfieldWI518 PPM30.3 GPGVery Hard518–529 PPM3 ZIPs · 2 sites100%strict rule
3IndependenceMO487 PPM28.5 GPGVery Hard485–486.5 PPM7 ZIPs · 3 sites100%strict rule
4BuckeyeAZ481 PPM28.1 GPGVery Hard239.5–481 PPM3 ZIPs · 3 sites100%strict rule
5LansingMI418 PPM24.4 GPGVery Hard417.5–417.5 PPM6 ZIPs · 3 sites100%strict rule
6Grand JunctionCO399 PPM23.3 GPGVery Hard393–405 PPM4 ZIPs · 3 sites100%strict rule
7AndersonIN387 PPM22.6 GPGVery Hard387–387 PPM3 ZIPs · 2 sites100%strict rule
8OrlandoFL374 PPM21.9 GPGVery Hard371–374 PPM13 ZIPs · 2 sites100%strict rule
9NaplesFL353 PPM20.6 GPGVery Hard325–384.5 PPM6 ZIPs · 2 sites100%strict rule
10Fort PierceFL348 PPM20.4 GPGVery Hard348–349 PPM5 ZIPs · 4 sites100%strict rule
11InwoodWV345 PPM20.2 GPGVery Hard344–344.5 PPM3 ZIPs · 2 sites100%strict rule
12Port St. LucieFL342 PPM20 GPGVery Hard324–348 PPM6 ZIPs · 4 sites100%strict rule
13CarmelIN340 PPM19.9 GPGVery Hard340–340 PPM3 ZIPs · 2 sites100%strict rule
14HaywardCA337 PPM19.7 GPGVery Hard334.5–354 PPM4 ZIPs · 2 sites100%strict rule
15PuebloCO331 PPM19.4 GPGVery Hard285–364 PPM5 ZIPs · 5 sites100%strict rule
16Bonita SpringsFL320 PPM18.7 GPGVery Hard319–320 PPM3 ZIPs · 2 sites100%strict rule
17Lehigh AcresFL308 PPM18 GPGVery Hard290–310.5 PPM6 ZIPs · 3 sites100%strict rule
18RuidosoNM288 PPM16.8 GPGVery Hard287.5–287.5 PPM3 ZIPs · 2 sites100%strict rule
19West Palm BeachFL284 PPM16.6 GPGVery Hard284–290.5 PPM6 ZIPs · 4 sites100%strict rule
20Fort LauderdaleFL282 PPM16.5 GPGVery Hard281.5–283 PPM10 ZIPs · 4 sites100%strict rule
21DavieFL282 PPM16.5 GPGVery Hard281–283 PPM4 ZIPs · 4 sites100%strict rule
22Pompano BeachFL282 PPM16.5 GPGVery Hard281–282 PPM4 ZIPs · 2 sites100%strict rule
23PlantationFL282 PPM16.5 GPGVery Hard282–283 PPM3 ZIPs · 3 sites100%strict rule
24SunriseFL282 PPM16.5 GPGVery Hard281–282 PPM3 ZIPs · 3 sites100%strict rule
25WestonFL282 PPM16.5 GPGVery Hard272.5–283 PPM3 ZIPs · 3 sites100%strict rule
26Pembroke PinesFL280 PPM16.4 GPGVery Hard279.5–280 PPM3 ZIPs · 3 sites100%strict rule
27StocktonCA278 PPM16.3 GPGVery Hard249–306 PPM3 ZIPs · 3 sites100%strict rule
28Palo AltoCA277 PPM16.2 GPGVery Hard261.5–292.5 PPM4 ZIPs · 2 sites100%strict rule
29MiramarFL276 PPM16.1 GPGVery Hard272.5–280 PPM4 ZIPs · 4 sites100%strict rule
30Cedar RapidsIA274 PPM16 GPGVery Hard272–295 PPM6 ZIPs · 5 sites100%strict rule
31HarrisonburgVA274 PPM16 GPGVery Hard273.5–277 PPM3 ZIPs · 2 sites100%strict rule
32North MiamiFL264 PPM15.4 GPGVery Hard264–272.5 PPM3 ZIPs · 2 sites100%strict rule
33SunnyvaleCA262 PPM15.3 GPGVery Hard233–261.5 PPM4 ZIPs · 2 sites100%strict rule
34MiamiFL261 PPM15.3 GPGVery Hard257–267.5 PPM19 ZIPs · 4 sites100%strict rule
35HialeahFL260 PPM15.2 GPGVery Hard257–264 PPM4 ZIPs · 2 sites100%strict rule
36WoodburyNY255 PPM14.9 GPGVery Hard54.9–268.5 PPM4 ZIPs · 2 sites100%strict rule
37HomesteadFL255 PPM14.9 GPGVery Hard255–256 PPM3 ZIPs · 3 sites100%strict rule
38Los AngelesCA254 PPM14.9 GPGVery Hard254–254 PPM5 ZIPs · 2 sites100%strict rule
39DowneyCA249 PPM14.6 GPGVery Hard246–249 PPM3 ZIPs · 2 sites100%strict rule
40LakewoodCA249 PPM14.6 GPGVery Hard243.5–249 PPM3 ZIPs · 2 sites100%strict rule
41AustinTX248 PPM14.5 GPGVery Hard247.5–247.5 PPM27 ZIPs · 4 sites100%strict rule
42MartinsburgWV244 PPM14.3 GPGVery Hard238–250 PPM4 ZIPs · 2 sites100%strict rule
43WhittierCA244 PPM14.3 GPGVery Hard243–245 PPM4 ZIPs · 3 sites100%strict rule
44RentonWA233 PPM13.6 GPGVery Hard232–232.5 PPM3 ZIPs · 2 sites100%strict rule
45OmahaNE224 PPM13.1 GPGVery Hard224–255 PPM29 ZIPs · 2 sites100%strict rule
46BellevueNE224 PPM13.1 GPGVery Hard224–224 PPM4 ZIPs · 2 sites100%strict rule
47RiversideCA217 PPM12.7 GPGVery Hard203–296.5 PPM8 ZIPs · 5 sites100%strict rule
48SchenectadyNY213 PPM12.5 GPGVery Hard213–213 PPM4 ZIPs · 3 sites100%strict rule
49San JoseCA202 PPM11.8 GPGVery Hard178.5–261.5 PPM30 ZIPs · 8 sites100%strict rule
50Wichita FallsTX199 PPM11.6 GPGVery Hard199–199 PPM6 ZIPs · 3 sites100%strict rule
51Colorado SpringsCO191 PPM11.2 GPGVery Hard187.5–200.5 PPM25 ZIPs · 17 sites100%strict rule
52MinneapolisMN191 PPM11.2 GPGVery Hard180.5–264 PPM21 ZIPs · 2 sites100%strict rule
53San BernardinoCA189 PPM11.1 GPGVery Hard183–196.5 PPM9 ZIPs · 6 sites100%strict rule
54JacksonvilleNC188 PPM11 GPGVery Hard183.5–194.5 PPM6 ZIPs · 3 sites100%strict rule
55San AntonioTX159 PPM9.3 GPGHard96.2–277.5 PPM56 ZIPs · 16 sites100%strict rule
56AlbanyGA156 PPM9.1 GPGHard155.5–157 PPM3 ZIPs · 3 sites100%strict rule
57Santa RosaCA140 PPM8.2 GPGHard135.5–141.5 PPM6 ZIPs · 4 sites100%strict rule
58JesupGA134 PPM7.8 GPGHard121–138 PPM3 ZIPs · 3 sites100%strict rule
59ShreveportLA133 PPM7.8 GPGHard133–243 PPM8 ZIPs · 3 sites100%strict rule
60PittsburghPA130 PPM7.6 GPGHard123–145 PPM24 ZIPs · 3 sites100%strict rule
61New YorkNY127 PPM7.4 GPGHard79.6–154 PPM89 ZIPs · 6 sites100%strict rule
62New RochelleNY127 PPM7.4 GPGHard127–127.5 PPM3 ZIPs · 2 sites100%strict rule
63YonkersNY126 PPM7.4 GPGHard122.5–126.5 PPM7 ZIPs · 2 sites100%strict rule
64NewarkNJ122 PPM7.1 GPGHard108–125 PPM9 ZIPs · 2 sites100%strict rule
65AlbuquerqueNM121 PPM7.1 GPGHard121–128 PPM14 ZIPs · 3 sites100%strict rule
66WilmingtonDE119 PPM7 GPGModerately Hard115–129 PPM6 ZIPs · 4 sites100%strict rule
67ConstantiaNY119 PPM7 GPGModerately Hard103–118.5 PPM3 ZIPs · 2 sites100%strict rule
68Fort WorthTX118 PPM6.9 GPGModerately Hard98.7–121 PPM11 ZIPs · 4 sites100%strict rule
69ArlingtonTX118 PPM6.9 GPGModerately Hard109.5–120 PPM9 ZIPs · 2 sites100%strict rule
70Grand PrairieTX118 PPM6.9 GPGModerately Hard117–119 PPM4 ZIPs · 2 sites100%strict rule
71PlanoTX118 PPM6.9 GPGModerately Hard117–118.5 PPM4 ZIPs · 3 sites100%strict rule
72DallasTX117 PPM6.8 GPGModerately Hard108–122 PPM45 ZIPs · 6 sites100%strict rule
73IrvingTX117 PPM6.8 GPGModerately Hard116–118 PPM6 ZIPs · 3 sites100%strict rule
74MesquiteTX116 PPM6.8 GPGModerately Hard115–115.5 PPM3 ZIPs · 2 sites100%strict rule
75WylieTX116 PPM6.8 GPGModerately Hard115.5–119 PPM3 ZIPs · 2 sites100%strict rule
76GarlandTX115 PPM6.7 GPGModerately Hard113.5–115.5 PPM5 ZIPs · 2 sites100%strict rule
77MercedCA115 PPM6.7 GPGModerately Hard104.5–133.5 PPM3 ZIPs · 3 sites100%strict rule
78DentonTX110 PPM6.4 GPGModerately Hard110–110 PPM7 ZIPs · 2 sites100%strict rule
79PhiladelphiaPA106 PPM6.2 GPGModerately Hard80.8–129 PPM49 ZIPs · 10 sites100%strict rule
80StatesboroGA103 PPM6 GPGModerately Hard102.8–106 PPM3 ZIPs · 2 sites100%strict rule
81WichitaKS86 PPM5 GPGModerately Hard86.2–92.2 PPM22 ZIPs · 4 sites100%strict rule
82FayettevilleAR79 PPM4.6 GPGModerately Hard74.3–89.3 PPM3 ZIPs · 3 sites100%strict rule
83CamdenNJ78 PPM4.6 GPGModerately Hard72.1–81.1 PPM5 ZIPs · 2 sites100%strict rule
84TrentonNJ75 PPM4.4 GPGModerately Hard69.9–80.9 PPM7 ZIPs · 2 sites100%strict rule
85WashingtonDC73 PPM4.3 GPGModerately Hard70.6–73.3 PPM57 ZIPs · 2 sites100%strict rule
86AlexandriaVA72 PPM4.2 GPGModerately Hard71–73 PPM6 ZIPs · 3 sites100%strict rule
87HoustonTX67 PPM3.9 GPGModerately Hard63.8–71.8 PPM21 ZIPs · 6 sites100%strict rule
88Las VegasNV66 PPM3.9 GPGModerately Hard65.8–65.8 PPM8 ZIPs · 2 sites100%strict rule
89ConroeTX65 PPM3.8 GPGModerately Hard63.1–65.4 PPM6 ZIPs · 3 sites100%strict rule
90AvondaleAZ64 PPM3.7 GPGModerately Hard64–64 PPM3 ZIPs · 2 sites100%strict rule
91DoverDE64 PPM3.7 GPGModerately Hard63.3–64.9 PPM3 ZIPs · 3 sites100%strict rule
92New BritainCT64 PPM3.7 GPGModerately Hard64.3–69.3 PPM3 ZIPs · 2 sites100%strict rule
93CarsonNV61 PPM3.6 GPGModerately Hard61–61 PPM3 ZIPs · 2 sites100%strict rule
94MemphisTN59 PPM3.5 GPGSoft52.7–63 PPM29 ZIPs · 22 sites100%strict rule
95NashuaNH58 PPM3.4 GPGSoft58–63.3 PPM4 ZIPs · 2 sites100%strict rule
96SurpriseAZ58 PPM3.4 GPGSoft54–64 PPM4 ZIPs · 2 sites100%strict rule
97BartlettTN56 PPM3.3 GPGSoft53.7–55.9 PPM3 ZIPs · 3 sites100%strict rule
98GlendaleAZ55 PPM3.2 GPGSoft54–64 PPM9 ZIPs · 3 sites100%strict rule
99PeoriaAZ55 PPM3.2 GPGSoft54–56 PPM3 ZIPs · 2 sites100%strict rule
100ScottsdaleAZ55 PPM3.2 GPGSoft55–238 PPM3 ZIPs · 2 sites100%strict rule

Ranking methodology

How this city ranking is calculated

We group ZIP profiles by city and state, then rank each city's median—not its maximum. To qualify, a city needs at least 3hardness readings, with at least 3that pass the strict ranking rule and at least 2distinct monitoring sites. 115 cities meet that rule in the current dataset.

Qualification reduces single-site outliers but does not turn environmental observations into utility or household results. Open any city to inspect distance, dates, source alignment, utility associations, and individual ZIP profiles.

Quick answer

Which US city has the hardest qualifying regional hardness evidence?

Fargo, ND is first in this research comparison with a qualifying regional median of 716 PPM (41.9 GPG), based on 4 observations.

This result describes qualifying regional environmental evidence. It must not be generalized to a utility or address without a current utility report or tap measurement.

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state ranking

Lower-hardness state evidence

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Lower-hardness city evidence

Compare up to 100 cities with the lowest qualifying source-aligned regional hardness observations and transparent provenance.