Hardness
Hard
138.5 PPM · 8.1 GPG
Local water dashboard
Official source aggregationA source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for San Juan County.
At a glance
EPA quarter 2026Q2
Hardness
Hard
138.5 PPM · 8.1 GPG
Compliance screen
Review needed
1 active health-based record
Lead 90th percentile
0 mg/L
0% of action level
Utility match
4 systems
Serves 47,655 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
138.5 PPM
Parts per million
138.5
mg/L as CaCO₃ equivalent
Grains per gallon
8.1
1 GPG ≈ 17.1 PPM
What this means at home
At 138.5 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.
USGS sites used
92
Nearest site
0.5 mi
Observation range
Feb 16, 2016–Mar 30, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: ANIMAS RIVER DISCRETE SAMPLE 20 (Stream).USGS source documentation ↗
Regional context
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Farmington median
137 PPM
About the same2 indexed ZIP readings · Range 135–138.5 PPM
New Mexico median
228 PPM
89 PPM lower194 indexed ZIP readings · Range 74.2–688.5 PPM
EPA benchmark screen
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
Lead (PB90)
0 mg/L
Reported Jun 30, 2026
Copper (CU90)
1.8 mg/L
Reported Dec 31, 2013
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0
EPA limit 0.015
Measured in mg/L
Local 1.8
EPA limit 1.3
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | NM3510024 | Unaddressed | Oct 1, 2025 |
| Groundwater RuleHealth-based | NM3510224 | Resolved | Sep 25, 2025through Feb 20, 2026 |
| Chlorine | NM3500224 | Resolved | Jun 1, 2025through Jun 30, 2025 |
| Interim Enhanced Surface Water Treatment Rule | NM3510224 | Resolved | Apr 1, 2025through Apr 30, 2025 |
| LEAD AND COPPER RULE REVISIONSHealth-based | NM3510024 | Resolved | Oct 17, 2024through Jul 14, 2025 |
| LEAD AND COPPER RULE REVISIONS | NM3510024 | Resolved | Oct 17, 2024through Jul 14, 2025 |
| Consumer Confidence Rule | NM3510024 | Resolved | Oct 1, 2024through Nov 21, 2024 |
| Public Notice | NM3510024 | Unaddressed | Aug 16, 2024 |
| Public Notice | NM3500224 | Unaddressed | Aug 16, 2024 |
| Public Notice | NM3500224 | Resolved | Sep 23, 2023through Jun 28, 2024 |
| Revised Total Coliform RuleHealth-based | NM3500224 | Resolved | Sep 12, 2023through Dec 17, 2024 |
| Public Notice | NM3500224 | Resolved | Sep 12, 2023through Dec 17, 2024 |
| Groundwater RuleHealth-based | NM3500224 | Resolved | Jul 29, 2023through Nov 1, 2024 |
| Groundwater RuleHealth-based | NM3500224 | Unaddressed | Jul 29, 2023 |
| Groundwater RuleHealth-based | NM3500224 | Resolved | Jul 29, 2023through Nov 1, 2024 |
| Public Notice | NM3500224 | Resolved | Apr 20, 2023through Jun 30, 2023 |
| Lead and Copper Rule | NM3510524 | Resolved | Oct 1, 2022through Jun 13, 2023 |
| Public Notice | NM3500224 | Resolved | Apr 17, 2022through Jan 8, 2025 |
| E. COLI | NM3500224 | Resolved | Apr 16, 2022through Apr 19, 2022 |
| Revised Total Coliform RuleHealth-based | NM3500224 | Resolved | Apr 1, 2022through Apr 30, 2022 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Matched to Farmington ZIP 87401 using 138.5 PPM nearby hardness and 2 reported measurement benchmarks.
Scale protection
138.5 PPM is 1× the high-hardness trigger used by this matcher.
Designed to reduce scale on fixtures, water heaters, glassware, and plumbing throughout the home.
Compare whole-house systemsDrinking water protection
Copper (90th percentile), Groundwater Rule have a measured benchmark flag or active health-based SDWIS record in this profile.
A certified multi-stage RO system targets a broader range of dissolved contaminants at the kitchen tap.
Explore under-sink filtrationAffiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.
Nearby indexed reports
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
EPA ECHO reports 1 active health-based violation among the associated community water systems. Review the affected utility's current notice and Consumer Confidence Report.
Nearby USGS observations produce an estimate of 138.5 PPM, or 8.1 grains per gallon, classified as hard. This is not a household tap measurement.
At 138.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.