Gardena Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
mixed
pH Level
7.5
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
165 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 Gardena, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Gardena | 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 Gardena compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Gardena, California | ≈ 120–179 mg/L | 4 ppt | 🟠 Hard | mixed |
| Lawndale, California | ≈ 120–179 mg/L | 6.1 ppt | 🟠 Hard | mixed |
| Hawthorne, California | 270 mg/L | 0 ppt | 🔴 Very Hard | reservoir |
| Westmont, California | ≈ 120–179 mg/L | 4.2 ppt | 🟠 Hard | mixed |
| Willowbrook, California | ≈ 180+ mg/L | 6.7 ppt | 🔴 Very Hard | mixed |
National Benchmark
How Gardena compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Gardena | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
Bring Scarsdale-quality water to your Gardena home
Shop water softeners on Amazon.com →
What Makes Gardena's Water Unique?
Local geology and source profile
Golden State Water Company provides drinking water to Gardena, California, in Los Angeles County, serving over 2.2 million people across 80 communities. The utility sources water from local groundwater aquifers in the Central Basin and San Pedro Basin, supplemented by imported surface water from the Metropolitan Water District of Southern California, including the Colorado River Aqueduct and State Water Project. Treatment occurs at the Consolidated Treatment Plant, with groundwater disinfected via chloramination and surface water receiving advanced filtration and oxidation processes.
The supply originates from the Los Angeles Basin watershed, with groundwater basins bounded by the Santa Monica and San Gabriel Mountains. Key aquifers include the pressurized Silverado and Lynwood formations within the San Pedro Basin, underlain by the Pico and Repetto siltstones of the Fernando Group (Pliocene-Pleistocene age). These marine-derived sedimentary rocks release dissolved calcium and magnesium as water percolates through them, producing a hard supply with elevated mineral content that influences taste, scaling, and soap lathering.
Hard water in Gardena leads to noticeable scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan while increasing energy costs. Maintenance tips include installing drain screens, flushing water heaters biannually, and using vinegar for spot cleaning. A water softener is recommended to protect household plumbing. Golden State Water reports no lead or copper action level exceedances in recent CCRs, and PFAS levels remain below detection limits following granular activated carbon treatment.
Geology & Source: Los Angeles Basin aquifers — San Pedro and West Coast Groundwater Basins; Quaternary alluvial over Pleistocene Fernando Formation limestone, dolomite, calcareous sandstone; calcium and magnesium dissolution produces hard water
Other California Water Reports
Report an Issue
Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.
All reports are reviewed by our team. Thank you for supporting data quality!
Frequently Asked Questions
Is Gardena's water safe to drink?
Do I need a water softener in Gardena?
How does Gardena compare to the USA average?
Data Sources & Methodology
Water quality data for Gardena 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.