Caldwell Water Hardness & Quality Report (2026)
Water Hardness
6.4 grains per gallon
Source
reservoir
pH Level
7.8
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
264.6 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 Caldwell, your appliances are currently losing 15% efficiency due to mineral buildup.
| Appliance | In Caldwell | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6 yrs | 8.5 yrs | -29% |
| Washing Machine | 9.5 yrs | 12 yrs | -21% |
| Water Heater | 11.2 yrs | 15 yrs | -25% |
Regional Water Comparison
How Caldwell compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Caldwell, Idaho | 109.5 mg/L | 2.3 ppt | 🟡 Moderately Hard | reservoir |
| Nampa, Idaho | 53.5 mg/L | 1.5 ppt | 🟢 Soft | reservoir |
| Meridian, Idaho | 113.5 mg/L | 2.3 ppt | 🟡 Moderately Hard | reservoir |
| Kuna, Idaho | 107 mg/L | 2.2 ppt | 🟡 Moderately Hard | reservoir |
| Eagle, Idaho | 61.5 mg/L | 1.6 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Caldwell compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Caldwell | 109.5 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Caldwell's Water Unique?
Local geology and source profile
Caldwell, Idaho, the Canyon County seat in the Treasure Valley on the Boise River — a major agricultural and food processing hub (J.R. Simplot Company, the largest potato processing operation in the world, operates near Caldwell), home of College of Idaho, and a fast-growing Treasure Valley community — draws its municipal water supply from the Treasure Valley Aquifer (Snake River Plain alluvial and basalt aquifer) via the City of Caldwell Water Division. Water hardness in Caldwell measures 109.5 mg/L — classified as moderately hard.
Caldwell's moderate hardness reflects the Treasure Valley's calcareous Snake River Plain geology. The Treasure Valley Aquifer in Canyon County consists of: Quaternary Boise River alluvial fan deposits (calcareous alluvial sand and gravel recharging from the Boise Mountains and Owyhee Mountains — moderate calcareous contribution from the Idaho Batholith granite and calcareous foothill formations); the Snake River Plain basalt (mafic basalt flows — calcium-moderate from plagioclase feldspar in the basalt); and the Pliocene–Pleistocene lake sediments (calcareous lacustrine deposits of the ancient Lake Idaho — contributing dissolved calcium). The moderate calcareous Treasure Valley alluvial and basalt terrain produces the moderate 109.5 mg/L at Caldwell.
At 109.5 mg/L, Caldwell 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 Caldwell Water Division consistently delivers water meeting all Idaho DEQ and EPA Safe Drinking Water Act requirements.
Geology & Source: Groundwater from the Treasure Valley Aquifer (Snake Plain Alluvial Aquifer) via the City of Caldwell Water Division — the Canyon County Boise Valley Quaternary basalt and alluvial deposits (Snake River Plain basalt and Boise River alluvial fan); moderately hard supply at 109.5 mg/L in Canyon County.