Water hardness in Stockton
3.4 gpg soft
Tap water in Stockton is soft: 3.4 gpg (58 mg/L · 3.2 °dH · 5.8 °fH).
Source: City of Stockton 2025 Annual Drinking Water Quality Report (2025) · data checked 2026-10-19
Range across supply zones: 53–351 mg/L.
3 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Delta Water Treatment Plant (surface water) | 3.1 | 53 | soft |
| groundwater wells | 14.1 | 242 | very hard |
| SEWD surface water (Stockton East Water District) | 3.4 | 58 | soft |
Stockton's 2025 report lists three supplies. Surface water from the Delta plant averages 53 mg/L and from Stockton East Water District 58 mg/L, while groundwater averages 242 mg/L (117 to 351). The page shows 58 mg/L (3.4 gpg), the median, which is soft. Addresses served mainly by wells receive very hard water, so check which supply reaches you.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 3.4 gpg |
|---|---|
| Utility | City of Stockton Municipal Utilities Department (Water) |
How Stockton compares
- Tap water in Stockton is 63 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1188 of 1372 in the United States (1 = hardest); 13 % of these cities have softer water.
- In California it is number 295 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: Galt, 35 km away (1.1 gpg).
- Nearest city with clearly harder water: Manteca, 19 km away (10.1 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Little or no limescale in kettles, water heaters or washing machines.
- Soap lathers easily; water does not dry skin or hair.
- Dishwasher: salt setting at minimum or off.
- No softener needed; a jug filter only changes taste.
How much salt will you use for softening?
No. Water this soft does not need softening.
Descale a coffee machine or kettle about every 6 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Stockton
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 3 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Stockton water hard or soft?
It is soft: 58 mg/L as CaCO₃ (3.4 gpg, 3.2 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Stockton 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 Stockton water?
3.4 gpg, equal to 3.2 °dH, 5.8 °fH or 58 mg/L calcium carbonate.
What dishwasher salt setting should I use in Stockton?
For 58 mg/L (3.2 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Stockton?
No. With soft water a softener adds nothing.
Source
Source: City of Stockton 2025 Annual Drinking Water Quality Report (2025). Method: figure published by the water supplier. City of Stockton 2025 Annual Drinking Water Quality Report · Outdated figure? Tell us