Hardness
Moderately Hard
85.9 PPM · 5 GPG
Local water dashboard
Official source aggregationWater quality in Trenton, NJ 08638
A source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Mercer County.
1 active health-based violation
- Primary matched system
- Trenton Water Works
- Source water
- Surface water
- County
- Mercer 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
0.006 mg/L
40% of action level
Utility match
1 system
Serves 217,000 people system-wide
Hardness meter
How hard is the water?
Estimated local hardness
USGS hardness classification scale
85.9 PPM
Soft
0–59Moderate
60–120Hard
121–180Very hard
181+
0–59Moderate
60–120Hard
121–180Very hard
181+
Parts per million
85.9
mg/L as CaCO₃ equivalent
Grains per gallon
5
1 GPG ≈ 17.1 PPM
What this means at home
At 85.9 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
423
Nearest site
2.4 mi
Observation range
Jan 12, 2016–Jun 9, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: Delaware River at Trenton NJ (Stream).USGS source documentation ↗
Regional context
Is 08638 typical?
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Trenton median
86 PPM
About the same7 indexed ZIP readings · Range 85.9–86 PPM
New Jersey median
81 PPM
5 PPM higher84 indexed ZIP readings · Range 47–121.5 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 pass1 fail
Lead (PB90)
0.006 mg/L
Reported Jun 30, 2026
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 0.006
EPA limit 0.015
TTHM
Measured in MG/L
Local 0.081
EPA limit 0.08
Share of EPA benchmark
100% line = listed limit
2026Q2
- All records
- 93
- Health-based
- 5
- Active health-based
- 1
| Contaminant or rule | System | Status | Period |
|---|---|---|---|
| TTHMHealth-basedReported 0.081 MG/L · MCL 0.08 | NJ1111001 | Archived | Oct 1, 2024through Dec 31, 2024 |
| Lead and Copper Rule | NJ1111001 | Resolved | Jul 1, 2024through Dec 31, 2024 |
| Total Haloacetic Acids (HAA5) | NJ1111001 | Resolved | Dec 28, 2023through Dec 20, 2024 |
| Revised Total Coliform Rule | NJ1111001 | Resolved | Nov 1, 2023through Nov 30, 2023 |
| Surface Water Treatment Rule | NJ1111001 | Resolved | Nov 1, 2023through Nov 30, 2023 |
| TTHM | NJ1111001 | Archived | Oct 1, 2023through Dec 31, 2023 |
| Revised Total Coliform Rule | NJ1111001 | Resolved | Oct 1, 2023through Oct 31, 2023 |
| Surface Water Treatment Rule | NJ1111001 | Resolved | Oct 1, 2023through Oct 31, 2023 |
| Total Haloacetic Acids (HAA5) | NJ1111001 | Archived | Oct 1, 2023through Dec 31, 2023 |
| Chlorine | NJ1111001 | Resolved | Oct 1, 2023through Dec 31, 2023 |
| Chlorine | NJ1111001 | Archived | Oct 1, 2023through Dec 31, 2023 |
| Lead and Copper Rule | NJ1111001 | Resolved | Sep 29, 2023through Jan 24, 2024 |
| Revised Total Coliform Rule | NJ1111001 | Resolved | Sep 1, 2023through Sep 30, 2023 |
| Surface Water Treatment Rule | NJ1111001 | Resolved | Sep 1, 2023through Sep 30, 2023 |
| Revised Total Coliform Rule | NJ1111001 | Resolved | Aug 1, 2023through Aug 31, 2023 |
| Surface Water Treatment Rule | NJ1111001 | Resolved | Aug 1, 2023through Aug 31, 2023 |
| Revised Total Coliform Rule | NJ1111001 | Resolved | Jul 1, 2023through Jul 31, 2023 |
| TTHM | NJ1111001 | Archived | Jul 1, 2023through Sep 30, 2023 |
| Total Haloacetic Acids (HAA5) | NJ1111001 | Archived | Jul 1, 2023through Sep 30, 2023 |
| Lead and Copper Rule | NJ1111001 | Resolved | Jul 1, 2023through Dec 31, 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 Trenton ZIP 08638 using 85.9 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 Trenton
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
Water questions for Trenton
Is tap water safe in Trenton?+
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 85.9 PPM, or 5 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.