South El Monte Water Hardness & Quality Report (2026)
Water Hardness
1.9 grains per gallon
Source
mixed
pH Level
7.2
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
66.1 mg/L
Est. Daily Cost
$0.09
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 South El Monte, your appliances are currently losing 4% efficiency due to mineral buildup.
| Appliance | In South El Monte | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.5 yrs | 8.5 yrs | — |
| Washing Machine | 12.4 yrs | 12 yrs | — |
| Water Heater | 14.3 yrs | 15 yrs | -5% |
Regional Water Comparison
How South El Monte compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ South El Monte, California | 33 mg/L | 2.8 ppt | 🟢 Soft | mixed |
| El Monte, California | 195.5 mg/L | 7.6 ppt | 🔴 Very Hard | mixed |
| Rosemead, California | 148.5 mg/L | 6.2 ppt | 🟠 Hard | mixed |
| Temple City, California | 129 mg/L | 5.6 ppt | 🟠 Hard | mixed |
| Avocado Heights, California | 48.5 mg/L | 3.3 ppt | 🟢 Soft | mixed |
National Benchmark
How South El Monte compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ South El Monte | 33 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes South El Monte's Water Unique?
Local geology and source profile
South El Monte, California, in Los Angeles County — an east San Gabriel Valley city adjacent to El Monte and Rosemead in the industrial east Los Angeles corridor — receives its municipal water from the South El Monte Water System or California Water Service, which draws from the Metropolitan Water District (MWD) import and the San Gabriel Valley Main Basin groundwater through local production wells in the San Gabriel Valley.
The very soft 33 mg/L hardness and low TDS of 66.1 mg/L are remarkably soft for the San Gabriel Valley — reflecting either a predominantly MWD State Water Project supply (SWP Sierra Nevada snowmelt — very soft) or a San Gabriel Basin groundwater zone that primarily recharges from the crystalline San Gabriel Mountains (San Gabriel Mountains Precambrian anorthosite, Cretaceous granodiorite of the Mount Lowe Granodiorite and San Gabriel Block). The San Gabriel Basin receives both MWD-imported recharge through the spreading grounds and natural mountain-front recharge from the San Gabriel River. The crystalline San Gabriel Mountains' granodiorite terrain contributes very soft, low-mineral water to the basin's recharge zones.
At 33 mg/L, South El Monte's water is very soft — excellent for household use. Scale essentially never forms, soap lathers abundantly, and appliances maintain maximum efficiency. Annual descaling is more than sufficient. The PFAS level of 2.8 ppt is very good for the east San Gabriel Valley industrial corridor — the San Gabriel Valley's long history of industrial contamination (the San Gabriel Valley Superfund sites are among the most extensive in California), yet the MWD import's dilution and treatment produces a relatively modest PFAS background for this densely industrial east LA corridor.
Geology & Source: South El Monte in Los Angeles County draws from the South El Monte Water System or California Water Service on MWD import blended with the San Gabriel Valley Groundwater Basin — the San Gabriel Basin alluvial aquifer taps Quaternary alluvial deposits from the San Gabriel Mountains (Cretaceous granodiorite) — granitic alluvial drainage produces very soft water at 33 mg/L with low TDS 66 mg/L in this east Los Angeles city.