Hardness
Very Hard
189.5 PPM · 11.1 GPG
Local water dashboard
Official source aggregationWater quality in Hollis, OK 73550
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Harmon County.
No active health-based violation reported
- Primary matched system
- Hollis
- Source water
- Groundwater
- County
- Harmon 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
0.0026 mg/L
17% of action level
Utility match
1 system
Serves 2,264 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
189.5 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
189.5
mg/L as CaCO₃ equivalent
Grains per gallon
11.1
1 GPG ≈ 17.1 PPM
What this means at home
At 189.5 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
2
Nearest site
52.9 mi
Observation range
Jun 15, 2016–May 10, 2021
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: ZB-05-44-907 (Well).USGS source documentation ↗
Regional context
Is 73550 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Hollis median
190 PPM
About the same1 indexed ZIP readings · Range 189.5–189.5 PPM
Oklahoma median
226 PPM
36 PPM lower148 indexed ZIP readings · Range 7–610 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 pass
Lead (PB90)
0.0026 mg/L
Reported Dec 31, 2024
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.
Lead (90th percentile)
Measured in mg/L
Local 0.0026
EPA limit 0.015
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 4
- Health-based
- 1
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Lead and Copper Rule | OK2002901 | Unaddressed | Oct 1, 2024 |
| Nitrate-NitriteHealth-basedReported 13 MG/L | OK2002901 | Resolved | Jul 1, 2024through Sep 30, 2024 |
| Total Haloacetic Acids (HAA5) | OK2002901 | Resolved | Oct 1, 2022through Sep 30, 2023 |
| TTHM | OK2002901 | Resolved | Oct 1, 2022through Sep 30, 2023 |
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 Hollis ZIP 73550 using 189.5 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
High-Capacity Whole House Water Softener
189.5 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
Water questions for Hollis
Is tap water safe in Hollis?+
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 189.5 PPM, or 11.1 grains per gallon, classified as very hard. This is not a household tap measurement.
Do I need a water softener?+
At 189.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.