Hardness
Moderately Hard
89.6 PPM · 5.2 GPG
Local water dashboard
Official source aggregationWater quality in Baltimore, MD 21231
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Baltimore City County.
1 reported benchmark flag
- Primary matched system
- City Of Baltimore
- Source water
- Surface water
- County
- Baltimore City 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
0.0027 mg/L
18% of action level
Utility match
1 system
Serves 1,600,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
89.6 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
89.6
mg/L as CaCO₃ equivalent
Grains per gallon
5.2
1 GPG ≈ 17.1 PPM
What this means at home
At 89.6 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
219
Nearest site
23.6 mi
Observation range
Jan 4, 2016–Jun 17, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: PATUXENT RIVER NEAR BOWIE, MD (Stream).USGS source documentation ↗
Regional context
Is 21231 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Baltimore median
90 PPM
About the same23 indexed ZIP readings · Range 88.1–94.6 PPM
Maryland median
90 PPM
About the same42 indexed ZIP readings · Range 57.8–167 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 pass1 fail
Lead (PB90)
0.0027 mg/L
Reported Dec 31, 2024
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
2 comparable results
Missing values remain blank; absence is not treated as a pass.
Lead (90th percentile)
Measured in mg/L
Local 0.0027
EPA limit 0.015
TTHM
Measured in UG/L
Local 81
EPA limit 0.08
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 9
- Health-based
- 2
- Active health-based
- 0
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| TTHMHealth-basedReported 81 UG/L · MCL 0.08 | MD0300002 | Archived | Jan 1, 2026through Mar 31, 2026 |
| LEAD AND COPPER RULE REVISIONS | MD0300002 | Resolved | Jul 2, 2025through Jul 2, 2025 |
| Chlordane | MD0300002 | Resolved | Apr 1, 2023through Jun 30, 2023 |
| Toxaphene | MD0300002 | Resolved | Apr 1, 2023through Jun 30, 2023 |
| Toxaphene | MD0300002 | Resolved | Apr 1, 2023through Jun 30, 2023 |
| Chlordane | MD0300002 | Resolved | Apr 1, 2023through Jun 30, 2023 |
| Nitrate | MD0300002 | Resolved | Jan 1, 2023through Dec 31, 2023 |
| Public Notice | MD0300002 | Resolved | Sep 5, 2022through Sep 6, 2022 |
| Revised Total Coliform RuleHealth-based | MD0300002 | Resolved | Sep 1, 2022through Sep 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
Your personalized water action plan
Matched to Baltimore ZIP 21231 using 89.6 PPM nearby hardness and 2 reported measurement benchmarks.
Drinking water protection
Under-Sink Reverse Osmosis System
TTHM has 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
Compare ZIPs in Baltimore
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Baltimore
Is tap water safe in Baltimore?+
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 89.6 PPM, or 5.2 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.