ZIP Code 93402 Water Quality Report

Los Osos, CA · San Luis Obispo County County

Safety Score

Water Safety Grade

Good — Minor issues on record

Health Violations

Total Violations

Lead Risk

High

Contaminants

About Tap Water in ZIP Code 93402

Tap water in ZIP code 93402 (Los Osos, CA) meets all federal safety standards and earns a solid B grade (score: 78/100). Served by Los Osos Community Services District, the water system has maintained general compliance with EPA Safe Drinking Water Act regulations, with only minor issues on record.

Water System

Los Osos Community Services District

EPA ID: CA4010016

Water Source

Ground Water

Population Served

7,086 residents

County

San Luis Obispo County County, California

🧪

Lead Levels in ZIP 93402

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

Lead Level: 5.1 ppb — Below Action Level

The 90th percentile lead level in 93402 is 5.1 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 exposure risk in 93402 is rated High. EPA models estimate a 57% probability of lead exposure risk in this ZIP code based on housing age, infrastructure age, and water system data. This typically reflects older housing stock built before 1986 (when lead pipes were banned), aging distribution infrastructure, or detected lead levels in water samples. Families should prioritize getting their tap water tested independently and installing a certified lead-reducing filter.

Lead Level (90th percentile)

5.10 ppb (0.0051 mg/L)

Lead Exposure Risk Rating

High

Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

57%

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.

📋

Violation History

Past 5 years — EPA SDWIS data

Los Osos Community Services District has recorded zero violations in the EPA compliance database over the past 5 years — a strong indicator of consistent regulatory compliance and careful monitoring.

Total Violations (5 yr)

Health-Based Violations

Unresolved Violations

Boil Water Advisories

Compliance Risk

Low

Regulatory compliance risk for Los Osos Community Services District is rated Low — indicating a consistent track record of meeting EPA reporting and treatment requirements.

⚗️

Contaminants Detected

Contaminants with health-based violations on record

No health-based contaminant violations are on record for ZIP code 93402. 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.

🌊

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

Energy Burden

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

3.51%

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

🛡 What Should You Do? — ZIP 93402 Recommendations

✓

Your water quality is good

Your water meets all EPA health standards. Standard precautions are sufficient for most residents.

✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
✓ Request your annual Consumer Confidence Report from Los Osos Community Services District
✓ 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 93402 Water Quality

Is tap water safe to drink in ZIP code 93402?+

Yes — tap water in 93402 (Los Osos, 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 93402 tap water?+

The 90th percentile lead level in 93402 is 5.1 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 93402?+

Tap water in ZIP code 93402 is provided by Los Osos Community Services District (EPA ID: CA4010016). This system serves approximately 7,086 residents. You can contact them directly for Consumer Confidence Reports, current advisories, and billing information.

What is the water source for 93402?+

ZIP code 93402 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 93402 have any active water quality violations?+

No active violations are on record for ZIP code 93402. 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 93402?+

Your water utility — Los Osos Community Services District — 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 "Los Osos Community Services District Consumer Confidence Report." The EPA's ECHO database also has historical compliance data.

What water filter should I use in 93402?+

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 93402, 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 93402 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 5.1 ppb in 93402, 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 93402 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 Los Osos Community Services District. 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 →