Simi Valley Water Hardness & Quality Report (2026)
Water Hardness
6.4 grains per gallon
Source
mixed
pH Level
7.7
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
279.7 mg/L
Est. Daily Cost
$0.29
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 Simi Valley, your appliances are currently losing 15% efficiency due to mineral buildup.
| Appliance | In Simi Valley | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6 yrs | 8.5 yrs | -29% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 11.2 yrs | 15 yrs | -25% |
Regional Water Comparison
How Simi Valley compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Simi Valley, California | 109 mg/L | 5.1 ppt | 🟡 Moderately Hard | mixed |
| Oak Park, California | 138.5 mg/L | 5.9 ppt | 🟠 Hard | mixed |
| Moorpark, California | 63.5 mg/L | 3.7 ppt | 🟡 Moderately Hard | mixed |
| Thousand Oaks, California | 188 mg/L | 7.4 ppt | 🔴 Very Hard | mixed |
| Agoura Hills, California | 32.5 mg/L | 2.8 ppt | 🟢 Soft | mixed |
National Benchmark
How Simi Valley compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Simi Valley | 109 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Simi Valley's Water Unique?
Local geology and source profile
Simi Valley, California, in eastern Ventura County northwest of Los Angeles, receives its municipal water supply through the Calleguas Municipal Water District (CMWD) and the Rancho Simi Recreation and Park District/City of Simi Valley Water Division, sourcing primarily from State Water Project (SWP) Delta water delivered via the Calleguas Pipeline System from Castaic Lake, and from local groundwater wells tapping the Simi Valley Groundwater Basin beneath the Simi Valley alluvial floor in Ventura County. Water hardness measures 109 mg/L — classified as moderately hard.
Simi Valley's moderate hardness reflects the blended character of SWP import water and local Simi Valley groundwater. The Simi Valley alluvial basin, underlain by Quaternary alluvial fan sediments derived from the surrounding Simi Hills and Santa Susana Mountains, receives recharge from precipitation and SWP percolation. The surrounding hillsides are dominated by the Cretaceous Chatsworth Formation (massive sandstone and conglomerate) and Conejo Volcanics (Miocene andesite and basalt) — both relatively low-calcium formations. The SWP import fraction brings moderate hardness from Sacramento Delta source water. The blended result is a moderately hard supply typical of inland Ventura County communities.
At 109 mg/L, Simi Valley residents encounter moderate scale accumulation in household use. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is a practical routine. Dishwashers produce cleaner glassware with rinse-aid, and water heaters benefit from annual inspection for element scale. Calleguas Municipal Water District and Simi Valley Water Division consistently deliver water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from State Water Project deliveries via the Calleguas Municipal Water District (CMWD) and local Simi Valley Groundwater Basin wells — SWP Delta water blended with local wells tapping Simi Valley alluvial fill derived from Simi Hills Cretaceous Chatsworth Formation sandstone and Conejo Volcanics produces moderately hard supply at 109 mg/L.