Hardness
Moderately Hard
72.9 PPM · 4.3 GPG
Local water dashboard
Official source aggregationWater quality in Oak Ridge, NC 27310
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Guilford County.
1 active health-based violation
- Primary matched system
- Arbor Run/charles Place S/d
- Source water
- Groundwater
- County
- Guilford County
- Profile updated
At a glance
What the current records say
EPA quarter 2026Q2
Compliance screen
Review needed
1 active health-based record
Lead 90th percentile
0 mg/L
0% of action level
Utility match
10 systems
Serves 576 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
72.9 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
72.9
mg/L as CaCO₃ equivalent
Grains per gallon
4.3
1 GPG ≈ 17.1 PPM
What this means at home
At 72.9 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
11
Nearest site
63.8 mi
Observation range
Aug 2, 2016–Sep 8, 2022
Estimate confidence
Low
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: DR-073 ELLERBE LB-1 0.18 MI BL SR1669 NR WEAVER NC (Hyporheic-zone well).USGS source documentation ↗
Regional context
Is 27310 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Oak Ridge median
73 PPM
About the same1 indexed ZIP readings · Range 72.9–72.9 PPM
North Carolina median
41 PPM
32 PPM higher519 indexed ZIP readings · Range 4.7–267.5 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 pass3 fail
Lead (PB90)
0 mg/L
Reported Jun 30, 2026
Copper (CU90)
1.5 mg/L
Reported Dec 31, 2021
Numerical coverage
4 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 1.5
EPA limit 1.3
Combined Radium (-226 and -228)
Measured in PCI/L
Local 6
EPA limit 5
Gross Alpha, Excl. Radon and U
Measured in PCI/L
Local 20
EPA limit 15
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 129
- Health-based
- 5
- Active health-based
- 1
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| Combined Radium (-226 and -228)Health-basedReported 6 PCI/L · MCL 5 | NC3041109 | Addressed | Apr 1, 2026through Jun 30, 2026 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 20 PCI/L · MCL 15 | NC3041130 | Archived | Jan 1, 2026through Mar 31, 2026 |
| Revised Total Coliform Rule | NC3041130 | Resolved | Nov 1, 2025through Nov 30, 2025 |
| Chlorine | NC3041130 | Resolved | Nov 1, 2025through Nov 30, 2025 |
| Chlorine | NC3041075 | Resolved | Nov 1, 2025through Nov 30, 2025 |
| Revised Total Coliform Rule | NC3041075 | Resolved | Nov 1, 2025through Nov 30, 2025 |
| Gross Alpha, Excl. Radon and UHealth-basedReported 16 PCI/L · MCL 15 | NC3041130 | Archived | Oct 1, 2025through Dec 31, 2025 |
| Endrin | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| BHC-GAMMA | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Methoxychlor | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Toxaphene | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Di(2-ethylhexyl) phthalate | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Picloram | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Atrazine | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| LASSO | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| 2,4,5-TP | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| HEXACHLOROBENZENE | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Benzo(a)pyrene | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| 1,2-DIBROMO-3-CHLOROPROPANE | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 2025 |
| Chlordane | NC3041130 | Resolved | Oct 1, 2025through Dec 31, 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 Oak Ridge ZIP 27310 using 72.9 PPM nearby hardness and 4 reported measurement benchmarks.
Drinking water protection
Under-Sink Reverse Osmosis System
Copper (90th percentile), Combined Radium (-226 and -228), Gross Alpha, Excl. Radon and U 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 Oak Ridge
Is tap water safe in Oak Ridge?+
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.
How hard is the water?+
Nearby USGS observations produce an estimate of 72.9 PPM, or 4.3 grains per gallon, classified as moderately hard. This is not a household tap measurement.
Do I need a water softener?+
There is no high-hardness trigger in this profile. Confirm with a tap test before buying equipment.