Highlands Ranch Water Hardness & Quality Report (2026)
Water Hardness
7.9 grains per gallon
Source
reservoir
pH Level
8
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
321.3 mg/L
Est. Daily Cost
$0.36
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 Highlands Ranch, your appliances are currently losing 18% efficiency due to mineral buildup.
| Appliance | In Highlands Ranch | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.1 yrs | 8.5 yrs | -40% |
| Washing Machine | 8.6 yrs | 12 yrs | -28% |
| Water Heater | 10.2 yrs | 15 yrs | -32% |
Regional Water Comparison
How Highlands Ranch compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Highlands Ranch, Colorado | 135.5 mg/L | 4.7 ppt | 🟠 Hard | reservoir |
| Southglenn, Colorado | 100.5 mg/L | 3.6 ppt | 🟡 Moderately Hard | reservoir |
| Greenwood Village, Colorado | 84.5 mg/L | 3.1 ppt | 🟡 Moderately Hard | reservoir |
| Castlewood, Colorado | 93 mg/L | 3.4 ppt | 🟡 Moderately Hard | reservoir |
| Littleton, Colorado | 83 mg/L | 3.1 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Highlands Ranch compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Highlands Ranch | 135.5 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Highlands Ranch's Water Unique?
Local geology and source profile
Highlands Ranch, Colorado, a major planned community in Douglas County south of Denver, receives its municipal water supply through the Centennial Water and Sanitation District, sourcing from Denver Water treated surface water (South Platte headwaters) delivered via the Denver Water regional distribution system, supplemented by the Centennial Water and Sanitation District's own Denver Basin aquifer groundwater wells tapping the Arapahoe Formation and Laramie–Fox Hills aquifers beneath Douglas County. Water hardness measures 135.5 mg/L — classified as moderately hard.
Highlands Ranch's moderate hardness reflects the blended character of the Centennial Water system in Douglas County. Denver Water's treated surface water — from the South Platte headwaters draining the Front Range Precambrian crystalline terrain (Pikes Peak Granite, Mount Evans batholith) — is inherently very soft. However, the Denver Basin aquifer in Douglas County, specifically the Arapahoe Formation (Late Cretaceous calcareous sandstone and shale) and Laramie–Fox Hills Formation groundwater, contributes moderate dissolved calcium and bicarbonate accumulated during extended subsurface residence in calcareous Cretaceous marine formations. The blend of soft surface water and moderately hard bedrock aquifer groundwater produces Highlands Ranch's moderately hard finished supply.
At 135.5 mg/L, Highlands Ranch residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. Dishwashers produce cleaner glassware with rinse-aid, and water heaters benefit from annual inspection for element scale. Centennial Water and Sanitation District and Denver Water consistently deliver water meeting all Colorado CDPHE and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from South Platte River headwaters via Denver Water regional distribution and the Centennial Water and Sanitation District — the Highlands Ranch service zone in Douglas County draws Denver Water treated water; the Front Range Precambrian Pike's Peak granite source water modified by the Denver Basin Arapahoe aquifer groundwater fraction produces moderately hard supply at 135.5 mg/L in southeast metro Denver.