Discovery Bay Water Hardness & Quality Report (2026)
Water Hardness
1.7 grains per gallon
Source
mixed
pH Level
7.2
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
58.3 mg/L
Est. Daily Cost
$0.08
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Discovery Bay, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In Discovery Bay | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.6 yrs | 8.5 yrs | — |
| Washing Machine | 12.5 yrs | 12 yrs | — |
| Water Heater | 14.4 yrs | 15 yrs | -4% |
Regional Water Comparison
How Discovery Bay compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Discovery Bay, California | 29 mg/L | 2.8 ppt | 🟢 Soft | mixed |
| Brentwood, California | 51 mg/L | 3.5 ppt | 🟢 Soft | mixed |
| Oakley, California | 145 mg/L | 6.2 ppt | 🟠 Hard | mixed |
| Antioch, California | 133.5 mg/L | 5.9 ppt | 🟠 Hard | mixed |
| Tracy, California | 70.5 mg/L | 4 ppt | 🟡 Moderately Hard | mixed |
National Benchmark
How Discovery Bay compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Discovery Bay | 29 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Discovery Bay's Water Unique?
Local geology and source profile
Discovery Bay, California, in Contra Costa County — a Contra Costa County community adjacent to Byron and Brentwood on the Sacramento-San Joaquin Delta in central California — receives its water from the Discovery Bay Community Services District, drawing from the Sacramento-San Joaquin Delta (Contra Costa County) through the central California Delta distribution.
The very soft 29 mg/L hardness and very low TDS of 58.3 mg/L place Discovery Bay among the softest water cities in this dataset — reflecting the Sacramento-San Joaquin Delta's supply of Sierra Nevada snowmelt runoff from the insoluble Jurassic granodiorite watershed, delivering some of the purest mountain water in California before it reaches the Delta. The Sacramento-San Joaquin Delta at Contra Costa County — Jurassic Sierra Nevada granodiorite (insoluble — primary dilutant from Sierra snowmelt), Cretaceous Coast Range formations (insoluble — dilutant), and Quaternary Delta alluvium (slightly calcareous — trace hardness contributor).
At 29 mg/L, Discovery Bay's water is very soft — no scale buildup, appliances last their full service life, and no softening is needed. Water is ideal for all uses. The PFAS level of 2.8 ppt is relatively low — warrants routine monitoring but no urgent filtration.
Geology & Source: Discovery Bay in Contra Costa County draws from the Discovery Bay Community Services District on the Sacramento-San Joaquin Delta (Contra Costa County, central California) — the Delta at Contra Costa County receives Sierra Nevada (Jurassic granodiorite — insoluble) runoff blended with SWP Northern California supply — California Contra Costa County Sacramento Delta Jurassic-Pleistocene insoluble supply produces very soft water at 29 mg/L with TDS 58.3 mg/L.