Water hardness in Trenton
6.3 gpg moderately hard
Tap water in Trenton is moderately hard: 6.3 gpg (107 mg/L · 6 °dH · 10.7 °fH).
Source: Trenton Water Works Annual Water Quality Report, Reporting Year 2025 (2025) · data checked 2026-10-23
Trenton Water Works draws water from the Delaware River upstream of the city and treats it at a conventional filtration plant on Route 29. River water from the Delaware is moderately hard, with 107 mg/L CaCO₃ here. Some scale builds up in kettles and heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6.3 gpg |
|---|---|
| Utility | Trenton Water Works (City of Trenton), PWS ID NJ1111001 |
How Trenton compares
- Tap water in Trenton is 31 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 981 of 1372 in the United States (1 = hardest); 28 % of these cities have softer water.
- In New Jersey it is number 22 of 34 cities; the regional median is 6.4 gpg.
- Nearest city with clearly softer water: Yardley, 9 km away (3.4 gpg).
- Nearest city with clearly harder water: Frenchtown, 44 km away (11.2 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Trenton
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Trenton water hard or soft?
It is moderately hard: 107 mg/L as CaCO₃ (6.3 gpg, 6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Trenton safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Trenton water?
6.3 gpg, equal to 6 °dH, 10.7 °fH or 107 mg/L calcium carbonate.
What dishwasher salt setting should I use in Trenton?
For 107 mg/L (6 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Trenton?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Trenton Water Works Annual Water Quality Report, Reporting Year 2025 (2025). Method: figure published by the water supplier. Trenton Water Works Annual Water Quality Report, Reporting Year 2025 · Outdated figure? Tell us