Rosemead Water Hardness & Quality Report (2026)
Water Hardness
8.7 grains per gallon
Source
mixed
pH Level
8
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
422.8 mg/L
Est. Daily Cost
$0.40
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 Rosemead, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Rosemead | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.7 yrs | 8.5 yrs | -45% |
| Washing Machine | 8.1 yrs | 12 yrs | -33% |
| Water Heater | 9.7 yrs | 15 yrs | -35% |
Regional Water Comparison
How Rosemead compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Rosemead, California | 148.5 mg/L | 6.2 ppt | 🟠 Hard | mixed |
| East San Gabriel, California | 152.5 mg/L | 6.3 ppt | 🟠 Hard | mixed |
| Temple City, California | 129 mg/L | 5.6 ppt | 🟠 Hard | mixed |
| San Gabriel, California | 185.5 mg/L | 7.3 ppt | 🔴 Very Hard | mixed |
| South El Monte, California | 33 mg/L | 2.8 ppt | 🟢 Soft | mixed |
National Benchmark
How Rosemead compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Rosemead | 148.5 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Rosemead's Water Unique?
Local geology and source profile
Rosemead, California, in the San Gabriel Valley of Los Angeles County adjacent to Monterey Park and El Monte — a densely populated San Gabriel Valley community with one of the largest Chinese-American populations in the United States, a major Asian-American business corridor along Valley Boulevard — draws its municipal water supply from the Main San Gabriel Valley Basin (combined groundwater pumping and MWD import) via the City of Rosemead Public Works Water Division. Water hardness in Rosemead measures 148.5 mg/L — classified as moderately hard.
Rosemead's moderate hardness reflects the San Gabriel Valley aquifer's blended supply. The Main San Gabriel Valley Basin is recharged from: MWD-imported Colorado River water (moderately hard, approximately 270–310 mg/L) percolated through San Gabriel spreading grounds; State Water Project Bay-Delta import (soft, approximately 50–100 mg/L) at the same spreading grounds; and local San Gabriel Mountains recharge — the San Gabriel Mountains (Transverse Ranges San Gabriel Formation granitic and calcareous terrain) contribute moderate dissolved calcium to the valley basin. The blended San Gabriel Valley groundwater at Rosemead produces the moderate 148.5 mg/L — characteristic of the central San Gabriel Valley water table.
At 148.5 mg/L, Rosemead residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. City of Rosemead Public Works Water Division consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from the Main San Gabriel Valley Basin (Upper and Lower zones) groundwater and Metropolitan Water District (MWD) import via the City of Rosemead Public Works Water Division — the San Gabriel Valley Quaternary alluvial aquifer (Colorado River and Bay-Delta import + San Gabriel Mountains recharge); moderately hard supply at 148.5 mg/L in Los Angeles County.