Pomona Water Hardness & Quality Report (2026)
Water Hardness
180+ mg/L
Very Hardestimated · not lab-verified
Source
reservoir
pH Level
8.2
neutral = 7.0
Lead
0.009 mg/L
✓ Below action level
TDS
545.2 mg/L
Est. Daily Cost
$0.91
energy & soap waste
Source: See methodology section below · 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 Pomona, your appliances are currently losing 45% efficiency due to mineral buildup.
| Appliance | In Pomona | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.7 yrs | 8.5 yrs | -45% |
| Washing Machine | 6.6 yrs | 12 yrs | -45% |
| Water Heater | 8.3 yrs | 15 yrs | -45% |
Regional Water Comparison
How Pomona compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Pomona, California | ≈ 180+ mg/L | 78.7 ppt | 🔴 Very Hard | reservoir |
| La Verne, California | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | reservoir |
| Claremont, California | ≈ 180+ mg/L | 7 ppt | 🔴 Very Hard | reservoir |
| Chino Hills, California | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | reservoir |
| Diamond Bar, California | ≈ 180+ mg/L | 7.3 ppt | 🔴 Very Hard | mixed |
National Benchmark
How Pomona compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Pomona | ≈ 180+ mg/L | 🔴 High |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Pomona's Water Unique?
Local geology and source profile
The City of Pomona Water Utility serves approximately 150,000 residents across a 23-square-mile area of Pomona in Los Angeles County, California. The supply is blended: 73% from local groundwater wells in Pomona and Claremont, treated at facilities removing volatile organic compounds, nitrate, and perchlorate; 7% surface water from the San Gabriel Mountains processed through the Frank G. Pedley Memorial Filtration Plant in Claremont; and 20% purchased from the Metropolitan Water District of Southern California (MWD), treated at the Weymouth Water Treatment Plant in La Verne, and from Three Valleys Municipal Water District (TVMWD), treated at the Miramar Water Treatment Plant in Claremont. This blend ensures reliability amid regional drought challenges.
The primary watershed encompasses the San Gabriel River and Pomona Valley drainages fed by the San Gabriel Mountains' San Antonio Canyon. Groundwater taps the Chino Basin aquifers, formed by alluvial fans depositing Mesozoic and Cenozoic sediments including granitic gneisses and schists that dissolve calcium and magnesium into the water, creating a hard supply. Surface contributions filter through fractured igneous and metamorphic terrains, while the overall carbonate-influenced alluvium shapes a mineralized profile typical of Southern California's inland valleys.
Very hard water in Pomona leads to significant scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency, shortening appliance lifespan, and increasing energy costs by up to 30%. Dry skin, soap scum, and spotted dishes are common household effects. Regular deliming of fixtures, drain screen installation, and flushing heaters is advised; a water softener is strongly recommended to prevent damage and improve usability. Water quality meets federal and state standards per reports, with treatment effectively addressing nitrate, perchlorate, and VOCs; arsenic exceedances from natural soil sources are noted in third-party assessments.
Geology & Source: Chino Basin Quaternary alluvial aquifers — calcium and magnesium from limestone and dolomite of the San Gabriel Mountains; San Antonio Canyon runoff through Mesozoic granitic and metamorphic rocks; carbonate alluvium yields hard supply
Other California Water Reports
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Frequently Asked Questions
Is Pomona's water safe to drink?
Do I need a water softener in Pomona?
How does Pomona compare to the USA average?
Data Sources & Methodology
Water quality data for Pomona is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
Water Hardness
Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
TDS — Total Dissolved Solids
Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.
PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances
EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.
Lead
Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.
Appliance Lifespan
Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.