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WaterSafeCheck
Official EPA SDWIS Verified ReportWater Quality & Testing GuideStatus: Normal Operations

ZIP Code 94591 Water Quality & Testing Report

Vallejo, CA · Solano County County · Updated for 2026

Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 94591 (Vallejo, CA)?

Yes, tap water in ZIP code 94591 (Vallejo, CA) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by City of Vallejo, the area earns an EPA Safety Grade of A (90/100) with 0 health violations, 1.4 ppb lead, and hard (124 mg/L / 7.3 GPG) water.

Safety Score
A

Water Safety Grade

Excellent — Meets all EPA standards

Health Violations

0

Total Violations

0

Lead Risk

Moderate

Contaminants

0

About Tap Water in ZIP Code 94591

Tap water in ZIP code 94591 (Vallejo, CA) is distributed by City of Vallejo (EPA ID: CA4810007), serving approximately 121,420 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of A with a composite quality score of 90/100.

Water System

City of Vallejo

EPA ID: CA4810007

Water Source

Surface Water

Population Served

121,420 residents

County

Solano County County, California

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Lead Levels in ZIP 94591

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

Lead Level: 1.4 ppb — Very Low

The 90th percentile lead level in 94591 is 1.4 ppb. This meets the EPA action level of 15 ppb. Health experts recommend a target of 0 ppb for optimal safety.

Lead exposure risk in 94591 is rated Moderate. EPA models estimate a 40% exposure probability based on housing and infrastructure age.

Lead Level (90th percentile)
1.40 ppb (0.0014 mg/L)
Copper (Consumer Confidence Report)

From annual CCR filing

0.7 ppb
Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

40%
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: Hard7.3 GPG · 124 mg/L

Water in ZIP 94591 is Hard (124 mg/L / 7.3 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

7.3 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

124 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: City of Vallejo · PWSID: CA4810007

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

City of Vallejo 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 94591 under the Safe Drinking Water Act.

From Consumer Confidence Report:

Copper (0.73 ppm); Trihalomethanes, Total (63 ppb); Haloacetic Acids, Sum of HAA5 (32 ppb)

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Water Source & Environmental Factors

Surface Water

This system draws water from lakes, rivers, or reservoirs. Surface water is treated to remove sediment, microorganisms, and chemical contaminants before reaching taps.

Water Source Type
Surface Water
CCR Source Classification
Surface water: Lake Berryessa (via Putah South Canal) and Lake Oroville (via Sacramento River and North Bay Aqueduct)
EPA Radon Zone

Lower potential

Zone 3
Annual Flood Risk Cost

Estimated annual flood-related costs per property

$0
Energy Burden

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

3.38%

EPA Radon Zone 3 — lower radon potential, though the EPA still recommends testing all homes.

Water Quality Testing in ZIP 94591

Tap Water & Well Testing Recommendations

Residents in ZIP code 94591 served by City of Vallejo 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 94591 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 Vallejo
  • ✓ 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 94591 Water Quality

Is tap water safe to drink in ZIP code 94591?+
Yes — tap water in 94591 (Vallejo, CA) meets EPA standards with a water safety grade of A. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 94591 (Vallejo, CA)?+
To test water quality in ZIP 94591, 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 94591?+
Tap water in 94591 is classified as Hard with an estimated mineral hardness of 124 mg/L (7.3 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 94591?+
Yes. Unlike municipal systems, private wells in 94591 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 94591 tap water?+
The 90th percentile lead level in 94591 is 1.4 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 94591?+
There are currently no active boil water advisories on record for 94591. Water treatment systems are operating within normal parameters.
Who provides tap water to 94591?+
Tap water in ZIP code 94591 is provided by City of Vallejo (EPA ID: CA4810007), serving approximately 121,420 residents.
What water filter should I use in 94591?+
Based on water metrics for 94591, 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 94591 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 Vallejo. 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 →