Oak Park Water Hardness & Quality Report (2026)
Water Hardness
8.1 grains per gallon
Source
mixed
pH Level
7.9
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
385.5 mg/L
Est. Daily Cost
$0.37
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 Oak Park, your appliances are currently losing 18% efficiency due to mineral buildup.
| Appliance | In Oak Park | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5 yrs | 8.5 yrs | -41% |
| Washing Machine | 8.5 yrs | 12 yrs | -29% |
| Water Heater | 10.1 yrs | 15 yrs | -33% |
Regional Water Comparison
How Oak Park compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Oak Park, California | 138.5 mg/L | 5.9 ppt | 🟠 Hard | mixed |
| Agoura, California | 32 mg/L | 2.8 ppt | 🟢 Soft | mixed |
| Agoura Hills, California | 32.5 mg/L | 2.8 ppt | 🟢 Soft | mixed |
| Thousand Oaks, California | 188 mg/L | 7.4 ppt | 🔴 Very Hard | mixed |
| Simi Valley, California | 109 mg/L | 5.1 ppt | 🟡 Moderately Hard | mixed |
National Benchmark
How Oak Park compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Oak Park | 138.5 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Oak Park's Water Unique?
Local geology and source profile
Oak Park, California, in Ventura County — a Ventura County community adjacent to Thousand Oaks and Agoura Hills in south California — receives its water from the Calleguas Municipal Water District, drawing from the State Water Project and local Conejo Creek watershed (Ventura County) through the south California distribution.
The moderately hard 138.5 mg/L hardness and TDS of 385.5 mg/L (TDS elevated relative to hardness — reflecting the SWP-blended supply's dissolved solids from the Colorado River and Calleguas distribution network) reflect the south California Ventura County supply's moderate calcareous character. The Ventura County water supply — State Water Project Northern California (very soft — dilutant), Colorado River via Metropolitan Water District (calcareous — primary hardness contributor), and local Conejo Creek watershed Quaternary alluvium (slightly calcareous — secondary contributor).
At 138.5 mg/L, Oak Park's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 5.9 ppt warrants a certified drinking water filter — Naval Air Station Point Mugu (Ventura County — AFFF) and the south California Ventura County corridor contribute to Oak Park's readings.
Geology & Source: Oak Park in Ventura County draws from the Calleguas Municipal Water District on the State Water Project and local Conejo Creek watershed (Ventura County, south California) — the SWP supply and local watershed draw from the Santa Monica Mountains (Cretaceous Simi Hills granite — insoluble) and Quaternary alluvial valley dissolution — California Ventura County SWP-Conejo Creek alluvial blend produces moderately hard water at 138.5 mg/L with TDS 385.5 mg/L.