Hardness
Hard
155.5 PPM · 9.1 GPG
Local water dashboard
Official source aggregationWater quality in Duncan, AZ 85534
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Greenlee County.
2 reported benchmark flags
- Primary matched system
- Duncan Town Of
- Source water
- Groundwater
- County
- Greenlee County
- Profile updated
At a glance
What the current records say
EPA quarter 2026Q2
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0 mg/L
0% of action level
Utility match
2 systems
Serves 605 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
155.5 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
155.5
mg/L as CaCO₃ equivalent
Grains per gallon
9.1
1 GPG ≈ 17.1 PPM
What this means at home
At 155.5 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
10
Nearest site
18.6 mi
Observation range
Mar 30, 2016–Apr 8, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: GILA RIVER BELOW BLUE CREEK, NEAR VIRDEN, NM (Stream).USGS source documentation ↗
Regional context
Is 85534 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Duncan median
156 PPM
About the same1 indexed ZIP readings · Range 155.5–155.5 PPM
Arizona median
241 PPM
85 PPM lower285 indexed ZIP readings · Range 66.4–1250 PPM
EPA benchmark screen
Contaminant snapshot
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
1 pass2 fail
Lead (PB90)
0 mg/L
Reported Dec 31, 2025
Copper (CU90)
1.6 mg/L
Reported Dec 31, 2019
Numerical coverage
3 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0
EPA limit 0.015
Copper (90th percentile)
Measured in mg/L
Local 1.6
EPA limit 1.3
Di(2-ethylhexyl) phthalate
Measured in MG/L
Local 0.007
EPA limit 0.006
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 128
- Health-based
- 4
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Revised Total Coliform Rule | AZ0406305 | Archived | Feb 1, 2026through Feb 28, 2026 |
| Di(2-ethylhexyl) phthalate | AZ0406001 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Revised Total Coliform Rule | AZ0406305 | Archived | Jan 1, 2026through Jan 31, 2026 |
| Lead and Copper Rule | AZ0406305 | Resolved | Jan 1, 2026through Mar 24, 2026 |
| Revised Total Coliform Rule | AZ0406305 | Archived | Dec 1, 2025through Dec 31, 2025 |
| Revised Total Coliform Rule | AZ0406305 | Resolved | Nov 1, 2025through Nov 30, 2025 |
| Public Notice | AZ0406001 | Resolved | Oct 2, 2025through Nov 17, 2025 |
| Consumer Confidence Rule | AZ0406305 | Unaddressed | Oct 2, 2025 |
| Lead and Copper Rule | AZ0406305 | Resolved | Oct 1, 2025through Nov 7, 2025 |
| Revised Total Coliform Rule | AZ0406305 | Resolved | Sep 1, 2025through Nov 3, 2025 |
| Revised Total Coliform Rule | AZ0406305 | Resolved | Aug 1, 2025through Aug 31, 2025 |
| Public Notice | AZ0406001 | Resolved | Jul 2, 2025through Sep 23, 2025 |
| Di(2-ethylhexyl) phthalate | AZ0406001 | Resolved | Jul 1, 2025through Sep 30, 2025 |
| Consumer Confidence Rule | AZ0406305 | Unaddressed | Jul 1, 2025 |
| DICHLOROMETHANE | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| o-Dichlorobenzene | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| trans-1,2-Dichloroethylene | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| 1,2-Dichloroethane | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| Carbon tetrachloride | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
| 1,2-Dichloropropane | AZ0406001 | Resolved | Apr 1, 2025through Jun 30, 2025 |
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Your personalized water action plan
Matched to Duncan ZIP 85534 using 155.5 PPM nearby hardness and 3 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
155.5 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
Under-Sink Reverse Osmosis System
Copper (90th percentile), Di(2-ethylhexyl) phthalate 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.
Frequently asked
Water questions for Duncan
Is tap water safe in Duncan?+
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.
How hard is the water?+
Nearby USGS observations produce an estimate of 155.5 PPM, or 9.1 grains per gallon, classified as hard. This is not a household tap measurement.
Do I need a water softener?+
At 155.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.