Patterson Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
groundwater
pH Level
8.2
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
513.3 mg/L
Est. Daily Cost
$0.40
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 Patterson, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Patterson | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Patterson compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Patterson, California | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | groundwater |
| Newman, California | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | groundwater |
| Ceres, California | ≈ 180+ mg/L | 117.2 ppt | 🔴 Very Hard | reservoir |
| Modesto, California | ≈ 180+ mg/L | 307.1 ppt | 🔴 Very Hard | reservoir |
| Salida, California | ≈ 120–179 mg/L | 5.9 ppt | 🟠 Hard | mixed |
National Benchmark
How Patterson compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Patterson | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Patterson's Water Unique?
Local geology and source profile
The City of Patterson Public Works Department supplies drinking water to approximately 22,000 residents in Patterson, Stanislaus County, California. The utility operates seven groundwater wells tapping the Delta-Mendota Subbasin, with no surface water sources or named treatment plants in available reports. Weekly sampling is conducted and analyzed by independent labs, with data accessible via the California Drinking Water Watch (SDWIS); there are currently no violations reported, and the system meets federal and state standards.
Patterson's water originates from the Delta-Mendota Subbasin within the San Joaquin Valley groundwater basin, formed by Pleistocene and Holocene alluvial deposits—sands, gravels, silts, and clays deposited by the San Joaquin River and ancestral waterways—overlying deeper limestone and dolomite bedrock. Mineral dissolution occurs as water moves through permeable gravels and fractures, with agricultural runoff and historical irrigation practices further contributing to the mineralised, hard profile.
At hard to very hard levels, Patterson's water promotes limescale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan. Faucet aerators and showerheads clog quickly, raising energy bills and causing dry skin and hair. Regular vinegar descaling, sediment filters, and scale-resistant appliances help mitigate effects; a water softener is recommended for households noticing spots on dishes or film on glassware. Water is routinely tested for over 100 contaminants; hexavalent chromium (Cr6) system averages 13–20.3 ppb (2024–2025) exceed the reinstated 10 ppb state MCL — reverse osmosis is advised for Cr6 reduction.
Geology & Source: Delta-Mendota Subbasin, Central Valley aquifer; Pleistocene-Holocene alluvial sediments — sands, gravels, silts, clays from San Joaquin River — overlying limestone/dolomite bedrock; mineral dissolution yields hard groundwater
Other California Water Reports
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Frequently Asked Questions
Is Patterson's water safe to drink?
Do I need a water softener in Patterson?
How does Patterson compare to the USA average?
Data Sources & Methodology
Water quality data for Patterson 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.