Hardness
Very Hard
286 PPM · 16.7 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 Navajo County.
At a glance
EPA quarter 2026Q2
Hardness
Very Hard
286 PPM · 16.7 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0 mg/L
0% of action level
Utility match
3 systems
Serves 4,833 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
286 PPM
Parts per million
286
mg/L as CaCO₃ equivalent
Grains per gallon
16.7
1 GPG ≈ 17.1 PPM
What this means at home
At 286 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
22
Nearest site
6.2 mi
Observation range
Jun 23, 2016–Mar 14, 2023
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: A-18-22 09DDC1 (Well).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.
Holbrook median
286 PPM
About the same1 indexed ZIP readings · Range 286–286 PPM
Arizona median
241 PPM
45 PPM higher285 indexed ZIP readings · Range 66.4–1250 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 Dec 31, 2025
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
1 comparable result
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0
EPA limit 0.015
100% line = listed limit
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | AZ0409015 | Unaddressed | Jan 1, 2026 |
| Lead and Copper Rule | AZ0401704 | Resolved | Jan 1, 2026through Mar 30, 2026 |
| Lead and Copper Rule | AZ0409046 | Unaddressed | Jan 1, 2026 |
| Chlorine | AZ0409015 | Archived | Oct 1, 2025through Oct 31, 2025 |
| LEAD AND COPPER RULE REVISIONS | AZ0409015 | Unaddressed | Jul 2, 2025 |
| Consumer Confidence Rule | AZ0409015 | Resolved | Jul 1, 2025through Oct 20, 2025 |
| TTHM | AZ0401704 | Resolved | Jan 1, 2025through Nov 12, 2025 |
| Total Haloacetic Acids (HAA5) | AZ0401704 | Resolved | Jan 1, 2025through Nov 12, 2025 |
| Revised Total Coliform Rule | AZ0409015 | Resolved | Dec 1, 2024through Dec 31, 2024 |
| Revised Total Coliform Rule | AZ0409015 | Resolved | Dec 1, 2024through Apr 21, 2025 |
| Public Notice | AZ0401704 | Resolved | Feb 16, 2024through Mar 25, 2024 |
| Public Notice | AZ0401704 | Resolved | Feb 11, 2024through Mar 25, 2024 |
| Public Notice | AZ0401704 | Resolved | Nov 4, 2023through Mar 20, 2024 |
| Revised Total Coliform Rule | AZ0409015 | Resolved | Nov 1, 2023through Nov 30, 2023 |
| Consumer Confidence Rule | AZ0401704 | Resolved | Oct 2, 2023through Jul 24, 2024 |
| Groundwater RuleHealth-based | AZ0409015 | Resolved | Jul 9, 2023through Aug 1, 2023 |
| Lead and Copper Rule | AZ0401704 | Resolved | Jul 1, 2023through Aug 23, 2023 |
| Chlorine | AZ0401704 | Resolved | Jul 1, 2023through Sep 30, 2023 |
| Consumer Confidence Rule | AZ0401704 | Resolved | Jul 1, 2023through Jul 24, 2024 |
| Public Notice | AZ0409046 | Resolved | May 21, 2023through Jun 5, 2024 |
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 Holbrook ZIP 86025 using 286 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
286 PPM is 2× 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 systemsAffiliate 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.
Frequently asked
EPA ECHO shows no active health-based violation for the associated systems in this reporting snapshot. This does not prove every contaminant is absent; federal records can lag and household plumbing can change tap conditions.
Nearby USGS observations produce an estimate of 286 PPM, or 16.7 grains per gallon, classified as very hard. This is not a household tap measurement.
At 286 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.