Water hardness in Milpitas
4.7 gpg moderately hard
Tap water in Milpitas is moderately hard: 4.7 gpg (80 mg/L · 4.5 °dH · 8 °fH).
Source: City of Milpitas 2025 Consumer Confidence Report (2025) · data checked 2026-10-23
Range across supply zones: 8–146 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| SFPUC supply | 3.5 | 60 | moderately hard |
| Valley Water supply | 5.9 | 101 | moderately hard |
Milpitas buys water from two wholesalers and normally keeps the supplies separate: SFPUC, mostly unfiltered Hetch Hetchy Sierra snowmelt, and Valley Water, which brings in Delta water via the South Bay Aqueduct. The two differ a lot, so the 2 zones span 8.1 to 146 mg/L CaCO₃ with a median of 80.2 mg/L. Check which supply serves your address.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 4.7 gpg |
|---|---|
| Utility | City of Milpitas (water purchased from SFPUC and Valley Water) |
How Milpitas compares
- Tap water in Milpitas is 48 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1107 of 1372 in the United States (1 = hardest); 19 % of these cities have softer water.
- In California it is number 269 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Hayward, 28 km away (3.5 gpg).
- Nearest city with clearly harder water: Santa Clara, 10 km away (15.8 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 Milpitas
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| 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 Milpitas water hard or soft?
It is moderately hard: 80 mg/L as CaCO₃ (4.7 gpg, 4.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Milpitas 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 Milpitas water?
4.7 gpg, equal to 4.5 °dH, 8 °fH or 80 mg/L calcium carbonate.
What dishwasher salt setting should I use in Milpitas?
For 80 mg/L (4.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Milpitas?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Milpitas 2025 Consumer Confidence Report (2025). Method: figure published by the water supplier. City of Milpitas 2025 Consumer Confidence Report · Outdated figure? Tell us