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WaterSafeCheck

ZIP Code 93401 Water Quality Report

San Luis Obispo, CA · San Luis Obispo County County

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

1

Total Violations

2

Lead Risk

Moderate

Contaminants

1

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Active Water Quality Issues Detected

EPA records show 0 unresolved violation. Contact San Luis Obispo Water Department for current status.

About Tap Water in ZIP Code 93401

Tap water in ZIP code 93401 (San Luis Obispo, CA) meets all federal safety standards and earns a solid B grade (score: 72/100). Served by San Luis Obispo Water Department, the water system has maintained general compliance with EPA Safe Drinking Water Act regulations, with only minor issues on record.

Water System

San Luis Obispo Water Department

EPA ID: CA4010009

Water Source

Surface Water

Population Served

47,788 residents

County

San Luis Obispo County County, California

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Lead Levels in ZIP 93401

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

Lead Level: 1.1 ppb — Very Low

The 90th percentile lead level in 93401 is 1.1 ppb, well below the EPA action level of 15 ppb. While this is a reassuring result, the EPA's public health goal for lead is actually zero — no amount of lead is considered completely safe, particularly for children under 6 and pregnant women. Running your tap for 30 seconds before use and using a certified NSF/ANSI 53 filter adds an extra layer of protection.

Lead exposure risk in 93401 is rated Moderate. EPA models estimate a 42% probability of lead exposure risk in this ZIP code based on housing age, infrastructure age, and water system data. This may reflect a mix of older and newer housing stock and infrastructure. Families with young children should test their home's water and consider a certified NSF/ANSI 53 water filter.

Lead Level (90th percentile)
1.10 ppb (0.0011 mg/L)
Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

42%
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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Violation History

Past 5 years — EPA SDWIS data

San Luis Obispo Water Department has recorded 1 health-based violation in the past 5 years. A single health violation means the water exceeded an EPA maximum contaminant level (MCL) at some point. Most water systems resolve these quickly, but residents should review the Consumer Confidence Report for details.

Total Violations (5 yr)
2
Health-Based Violations
1
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
Moderate

Regulatory compliance risk is rated Moderate. San Luis Obispo Water Department has had occasional lapses in compliance but generally meets Safe Drinking Water Act requirements.

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Contaminants Detected

Contaminants with health-based violations on record

EPA records identify 1 contaminant associated with health-based violations in ZIP code 93401: Consumer Confidence Report Rule. These contaminants exceeded the Maximum Contaminant Levels (MCLs) established by the EPA under the Safe Drinking Water Act at some point in the 5-year monitoring period. The presence of these violations does not necessarily mean water is currently unsafe — water systems are often required to increase monitoring and treatment when violations occur. Review the annual Consumer Confidence Report for the most current status.

Consumer Confidence Report Rule

⚖ Enforcement Actions

4 enforcement actions have been issued against San Luis Obispo Water Department — a high number that reflects sustained compliance struggles. Enforcement actions escalate from administrative orders to financial penalties when utilities repeatedly fail to meet safe drinking water standards.
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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
EPA Radon Zone

Moderate potential

Zone 2
Annual Flood Risk Cost

Estimated annual flood-related costs per property

$1
Energy Burden

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

3.82%

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

🛡 What Should You Do? — ZIP 93401 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from San Luis Obispo Water Department
  • ✓ 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

Frequently Asked Questions — ZIP 93401 Water Quality

Is tap water safe to drink in ZIP code 93401?+
Yes — tap water in 93401 (San Luis Obispo, CA) currently meets all federal EPA standards with a water safety grade of B. No health-based violations are on record in the past 5 years. You can drink your tap water with confidence, though running the tap for 30 seconds in the morning is always a good practice.
What is the lead level in 93401 tap water?+
The 90th percentile lead level in 93401 is 1.1 ppb (parts per billion). The EPA action level is 15 ppb. This is a low level, well below the EPA action level of 15 ppb.
Who provides tap water to 93401?+
Tap water in ZIP code 93401 is provided by San Luis Obispo Water Department (EPA ID: CA4010009). This system serves approximately 47,788 residents. You can contact them directly for Consumer Confidence Reports, current advisories, and billing information.
What is the water source for 93401?+
ZIP code 93401 is served by surface water. Surface water systems draw from rivers, lakes, or reservoirs and must meet strict EPA treatment requirements including filtration and disinfection.
Does 93401 have any active water quality violations?+
There are 1 health-based violation in the past 5-year record, but no currently unresolved violations according to EPA data. This means past issues have been addressed.
How do I get a copy of my water quality report for 93401?+
Your water utility — San Luis Obispo Water Department — is required by law to send you an annual Consumer Confidence Report (CCR) by July 1 each year. You can also request it directly from the utility or find it online by searching "San Luis Obispo Water Department Consumer Confidence Report." The EPA's ECHO database also has historical compliance data.
What water filter should I use in 93401?+
The right filter depends on what contaminants are present. For lead, look for a filter certified to NSF/ANSI Standard 53. For chlorine byproducts (like THMs), NSF/ANSI 42 filters work well. For a broad range of contaminants including PFAS, look for NSF/ANSI 58 (reverse osmosis) systems. For ZIP code 93401, with detected contaminants including Consumer Confidence Report Rule, a multi-stage filter or reverse osmosis system is recommended.
Is 93401 tap water safe for babies and infants?+
Infants are especially vulnerable to lead, nitrates, and microbial contaminants in drinking water. Current EPA data for 93401 shows a lead level of 1.1 ppb — below the action level, but as an extra precaution, run your tap for 30 seconds before use and consider a certified lead filter for infant formula. Always consult your pediatrician for guidance specific to your child's health.

Data Sources & Methodology

Water quality data for ZIP code 93401 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 San Luis Obispo Water Department. 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 →