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Official EPA SDWIS Verified ReportWater Quality & Testing GuideHistorical Record: No Recorded SDWIS Violations

ZIP Code 93640 Water Quality & Testing Report

Mendota, CA · Fresno County County · Updated for 2026

Sahajul HaqueCompiled & verified by Sahajul Haque from official EPA SDWIS records
Public Health & Medical Notice: Drinking water quality data on this page reflects historical compliance records submitted under the Safe Drinking Water Act. This information does not constitute medical advice or a real-time safety guarantee. If you are pregnant, nursing, preparing infant formula, or immunocompromised, consult a healthcare provider. Boiling water kills biological pathogens, but does NOT remove chemical contaminants like lead, arsenic, or PFAS.
Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 93640 (Mendota, CA)?

Yes, tap water in ZIP code 93640 (Mendota, CA) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by City of Mendota,, the area earns an EPA Safety Grade of B (75/100) with 0 health violations, 0 ppb lead, and hard (168 mg/L / 9.8 GPG) water.

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

0

Total Violations

0

Lead Risk

Moderate

Contaminants

0

About Tap Water in ZIP Code 93640

Tap water in ZIP code 93640 (Mendota, CA) is distributed by City of Mendota, (EPA ID: CA1010021), serving approximately 11,404 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of B with a composite quality score of 75/100.

Water System

City of Mendota,

EPA ID: CA1010021

Water Source

Ground Water

Population Served

11,404 residents

County

Fresno County County, California

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Lead Levels in ZIP 93640

EPA action level: 15 ppb | Public health goal: 0 ppb

Lead Data Not Available

Lead testing data was not found in EPA records for ZIP code 93640. Contact City of Mendota, to request lead testing results.

Lead exposure risk in 93640 is rated Moderate. EPA models estimate a 31% exposure probability based on housing and infrastructure age.

Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

31%
Note: Lead levels above are the 90th percentile from EPA monitoring — meaning 90% of samples were at or below this level. Even "undetected" tap water lead doesn't account for lead leaching from home plumbing. If your home was built before 1986, individual tap testing is recommended.
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Water Hardness & Mineral Content

Grains per gallon (GPG) & Parts per million (PPM / mg/L)

Classification: Hard9.8 GPG · 168 mg/L

Water in ZIP 93640 is Hard (168 mg/L / 9.8 GPG). Residents may notice white mineral spots on glassware, reduced soap efficiency, and mineral scale on faucets and showerheads.

Recommendation: An ion-exchange water softener or descaler is recommended to prolong the life of water heaters, dishwashers, and plumbing.
Hardness (GPG)

Grains per gallon

9.8 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

168 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: City of Mendota, · PWSID: CA1010021

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

City of Mendota, has recorded zero violations in the EPA compliance database over the past 5 years.

Total Violations (5 yr)
0
Health-Based Violations
0
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
Low

Regulatory compliance risk for this utility is rated Low based on past reporting and enforcement records.

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Contaminants Detected

Contaminants with health-based violations on record

No health-based contaminant violations are on record for ZIP code 93640 under the Safe Drinking Water Act.

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Water Source & Environmental Factors

Ground Water

This system draws water from underground aquifers. Groundwater is naturally filtered through soil and rock, but can still contain naturally occurring minerals like arsenic, radium, or nitrates.

Water Source Type
Ground Water
EPA Radon Zone

Moderate potential

Zone 2
Annual Flood Risk Cost

Estimated annual flood-related costs per property

$0
Energy Burden

% of household income spent on energy — indicator of older infrastructure

7.92%

EPA Radon Zone 2 — moderate radon potential. The EPA recommends testing your home regardless of zone designation.

Water Quality Testing in ZIP 93640

Tap Water & Well Testing Recommendations

Residents in ZIP code 93640 served by City of Mendota, can test tap water or private well systems to verify water purity. Testing detects hidden contaminants before they impact family health.

Tap Water Testing Steps

  • 1.Conduct a certified lead check if your home was constructed before 1986.
  • 2.Use certified lab testing kits rather than uncalibrated test strips for regulated compliance.
  • 3.Sample water from both your kitchen faucet and water heater to compare line purity.

Private Well Testing Steps

  • •Test for Coliform bacteria and Nitrates annually.
  • •Test for heavy metals, radon, and PFAS every 3 years.
  • •Send samples to a state-certified drinking water laboratory recognized by California State Water Resources Control Board.
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in CA for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 93640 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from City of Mendota,
  • ✓ If your home was built before 1986, consider testing your own tap for lead
  • ✓ Use a pitcher filter (NSF/ANSI 42 certified) for improved taste

Recommended Taste & Safety Filter:

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NSF/ANSI 53 Certified Pitcher Filter

Best for removing aesthetic chlorine, odors, and low-level heavy metals.

Filter Selection Guide →

Frequently Asked Questions — ZIP 93640 Water Quality

Is tap water safe to drink in ZIP code 93640?+
Yes — tap water in 93640 (Mendota, CA) meets EPA standards with a water safety grade of B. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 93640 (Mendota, CA)?+
To test water quality in ZIP 93640, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in CA. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact California State Water Resources Control Board for a list of certified regional labs.
How hard is the tap water in 93640?+
Tap water in 93640 is classified as Hard with an estimated mineral hardness of 168 mg/L (9.8 GPG). An ion-exchange water softener or descaler is recommended to prolong the life of water heaters, dishwashers, and plumbing.
Should I test private well water in 93640?+
Yes. Unlike municipal systems, private wells in 93640 are not regulated by the EPA or local utilities. Private well owners should test their water annually for coliform bacteria and nitrates, and every 3 to 5 years for heavy metals (lead, arsenic) and volatile organic compounds.
What is the lead level in 93640 tap water?+
Lead level data is not available in EPA records for 93640. Contact your utility for details.
Is there an active boil water notice in 93640?+
There are currently no active boil water advisories on record for 93640. Water treatment systems are operating within normal parameters.
Who provides tap water to 93640?+
Tap water in ZIP code 93640 is provided by City of Mendota, (EPA ID: CA1010021), serving approximately 11,404 residents.
What water filter should I use in 93640?+
Based on water metrics for 93640, we recommend None / Standard Pitcher. Look for certifications such as NSF/ANSI 42 (Chlorine, Taste & Odor).

Data Sources & Methodology

Water quality data for ZIP code 93640 is compiled from the EPA Safe Drinking Water Information System (SDWIS), EPA ECHO enforcement database, UCMR5 unregulated contaminant monitoring, and Consumer Confidence Reports filed by City of Mendota,. Safety scores are composite metrics derived from violation history, lead levels, enforcement actions, and infrastructure risk indicators. Data reflects a 5-year monitoring window. Last dataset update: 2024. View EPA source data →