How does Selma's water compare to the national average?

The USA national average is 151 mg/L. Selma (51 mg/L) is 100 mg/L softer than average.

Selma Water Hardness & Quality Report (2026)

Water Hardness

51mg/L

Soft

3 grains per gallon

Source

groundwater

pH Level

8.1

neutral = 7.0

Lead

0.008 mg/L

✓ Below action level

TDS

494.4 mg/L

Est. Daily Cost

$0.14

energy & soap waste

Source: See methodology section below · Updated 2026

51mg/L as CaCO₃Soft

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 Selma, your appliances are currently losing 7% efficiency due to mineral buildup.

Appliance	In Selma	Soft Water City	Efficiency Loss
Kettle	7.9 yrs	8.5 yrs	-7%
Washing Machine	11.7 yrs	12 yrs	-3%
Water Heater	13.6 yrs	15 yrs	-9%

Regional Water Comparison

How Selma compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Selma, California	51 mg/L	6.8 ppt	🟢 Soft	groundwater
Kingsburg, California	169.5 mg/L	0 ppt	🟠 Hard	groundwater
Parlier, California	≈ 180+ mg/L	0 ppt	🔴 Very Hard	groundwater
Sanger, California	≈ 120–179 mg/L	39.7 ppt	🟠 Hard	groundwater
Reedley, California	≈ 120–179 mg/L	0 ppt	🟠 Hard	groundwater

National Benchmark

How Selma compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Selma	51 mg/L	🟢 None
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Selma's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 494.4 mg/LpH: 8.1

California Water Service (CWS) operates the Selma District water system, serving approximately 25,000–26,000 residents in Selma, California. The utility draws its entire supply from groundwater sources within the San Joaquin Valley aquifer system. The Selma District office is located at 2042 2nd Street, Selma, CA 93662, and can be reached at (559) 896-4546. All water is sourced from groundwater; no surface water intakes are used in this system.

The Selma water supply originates from the San Joaquin Valley's Quaternary alluvial aquifer and Tertiary sedimentary formations. These younger geological deposits — composed of sand, gravel, and silt layers shaped by Pleistocene and Holocene alluvial processes — have limited exposure to heavily mineralized carbonate or evaporite rock formations. As a result, the groundwater remains relatively soft compared to deeper valley aquifers that contact more mineralized strata.

With a soft hardness profile, Selma's water poses minimal scaling concerns for household plumbing and appliances. Soap lathers effectively, mineral buildup on fixtures is unlikely, and water softening is not recommended for most residential users. According to the 2024 Consumer Confidence Report, CWS–Selma's water meets all EPA Maximum Contaminant Level Goals with no health-based violations and no recommended action items for customers.

Geology & Source: San Joaquin Valley aquifer; Quaternary alluvial deposits and Tertiary sedimentary formations — younger alluvial geology with limited carbonate or evaporite exposure produces soft groundwater

Other California Water Reports

Kingsburg

169.5 mg/L

🟠 Hard

Parlier

≈ 180+ mg/L

🔴 Very Hard

Sanger

≈ 120–179 mg/L

🟠 Hard

Reedley

≈ 120–179 mg/L

🟠 Hard

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 Selma's water safe to drink?

Yes. Selma's water meets all federal safety standards. The hardness is 51 mg/L (Soft), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Selma?

Selma's water is soft at 51 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.

How does Selma compare to the USA average?

The USA national average is 151 mg/L. Selma (51 mg/L) is 100 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Selma is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

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.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

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.

Measured

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.

Modelled

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.

Calculated

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.