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WaterSafeCheck

ZIP Code 93423 Water Quality Report

Atascadero, CA · San Luis Obispo County County

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

0

Total Violations

3

Lead Risk

N/A

Contaminants

0

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Active Water Quality Issues Detected

EPA records show 0 unresolved violation. Contact Atascadero Mutual Water Company for current status.

About Tap Water in ZIP Code 93423

Tap water in ZIP code 93423 (Atascadero, CA) meets all federal safety standards and earns a solid B grade (score: 78/100). Served by Atascadero Mutual Water Company, the water system has maintained general compliance with EPA Safe Drinking Water Act regulations, with only minor issues on record.

Water System

Atascadero Mutual Water Company

EPA ID: CA4010002

Water Source

Ground Water

Population Served

30,618 residents

County

San Luis Obispo County County, California

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Lead Levels in ZIP 93423

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

Lead Level: 6.1 ppb — Below Action Level

The 90th percentile lead level in 93423 is 6.1 ppb, below the EPA action level of 15 ppb but above what many health experts consider ideal. The CDC and EPA both affirm there is no safe level of lead exposure for children. Families with young children or pregnant women should consider a certified NSF/ANSI 53 water filter, and request lead testing of their home's tap water.
Lead Level (90th percentile)
6.10 ppb (0.0061 mg/L)
Copper Level (90th percentile)

EPA action level: 1.3 mg/L

1.5 mg/L
Lead Exposure Risk Rating
Unknown
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

Atascadero Mutual Water Company has recorded 3 violations, but none are health-based. Administrative or reporting violations don't directly indicate unsafe water, but they do signal gaps in documentation or monitoring procedures.

Total Violations (5 yr)
3
Health-Based Violations
0
Unresolved Violations
0
Boil Water Advisories
0
Compliance Risk
Moderate

Regulatory compliance risk is rated Moderate. Atascadero Mutual Water Company 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

No health-based contaminant violations are on record for ZIP code 93423. This means EPA monitoring has not found levels of regulated contaminants exceeding the Maximum Contaminant Levels (MCLs) set under the Safe Drinking Water Act — a positive indicator of water quality compliance.

From Consumer Confidence Report:

Turbidity (5 NTU*)

⚖ Enforcement Actions

4 enforcement actions have been issued against Atascadero Mutual Water Company — 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

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
CCR Source Classification
Surface Water and Ground Water
EPA Radon Zone

Moderate potential

Zone 2

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

🛡 What Should You Do? — ZIP 93423 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Atascadero Mutual Water Company
  • ✓ 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 93423 Water Quality

Is tap water safe to drink in ZIP code 93423?+
Yes — tap water in 93423 (Atascadero, 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 93423 tap water?+
The 90th percentile lead level in 93423 is 6.1 ppb (parts per billion). The EPA action level is 15 ppb. This is below the action level, but some health experts recommend a lead filter for families with young children.
Who provides tap water to 93423?+
Tap water in ZIP code 93423 is provided by Atascadero Mutual Water Company (EPA ID: CA4010002). This system serves approximately 30,618 residents. You can contact them directly for Consumer Confidence Reports, current advisories, and billing information.
What is the water source for 93423?+
ZIP code 93423 is served by ground water. Groundwater systems draw from underground aquifers. While naturally filtered, groundwater can still contain naturally occurring contaminants such as arsenic, radium, or nitrates at elevated levels in some regions.
Does 93423 have any active water quality violations?+
No active violations are on record for ZIP code 93423. EPA data shows this water system is currently in compliance with Safe Drinking Water Act standards.
How do I get a copy of my water quality report for 93423?+
Your water utility — Atascadero Mutual Water Company — 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 "Atascadero Mutual Water Company Consumer Confidence Report." The EPA's ECHO database also has historical compliance data.
What water filter should I use in 93423?+
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 93423, with a clean compliance record, a standard carbon block filter meeting NSF/ANSI 42 is a good choice for taste and as a precaution.
Is 93423 tap water safe for babies and infants?+
Infants are especially vulnerable to lead, nitrates, and microbial contaminants in drinking water. Given the detected lead level of 6.1 ppb in 93423, we recommend using a certified NSF/ANSI 53 water filter or certified bottled water for preparing infant formula. Always consult your pediatrician for guidance specific to your child's health.

Data Sources & Methodology

Water quality data for ZIP code 93423 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 Atascadero Mutual Water Company. 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 →