Water hardness in Rochester
6.1 gpg moderately hard
Tap water in Rochester is moderately hard: 6.1 gpg (104 mg/L · 5.8 °dH · 10.4 °fH).
Source: City of Rochester 2025 Water Quality Report (2025) · data checked 2026-10-20
Range across supply zones: 88–120 mg/L.
4 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Hemlock Lake source (Hemlock Water Filtration Plant) | 5.1 | 88 | moderately hard |
| Hemlock Lake supply | 5.1 | 88 | moderately hard |
| Lake Ontario (MCWA) supply | 7 | 120 | hard |
| Lake Ontario source (MCWA purchased water) | 7 | 120 | hard |
Rochester uses Hemlock and Canadice Lakes, two Finger Lakes in a protected state forest, and water from Lake Ontario bought from the Monroe County Water Authority. Depending on the season, a neighborhood gets one source or a blend, which gives 88–120 mg/L across 4 zones. Hardness is 104 mg/L CaCO₃ overall, so some scale builds up in kettles.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6.1 gpg |
|---|---|
| Utility | City of Rochester Water Bureau |
How Rochester compares
- Tap water in Rochester is 33 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 996 of 1372 in the United States (1 = hardest); 27 % of these cities have softer water.
- In New York it is number 8 of 16 cities; the regional median is 5.2 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 Rochester
| 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 Rochester water hard or soft?
It is moderately hard: 104 mg/L as CaCO₃ (6.1 gpg, 5.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rochester 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 Rochester water?
6.1 gpg, equal to 5.8 °dH, 10.4 °fH or 104 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rochester?
For 104 mg/L (5.8 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Rochester?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Rochester 2025 Water Quality Report (2025). Method: figure published by the water supplier. City of Rochester 2025 Water Quality Report · Outdated figure? Tell us