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WaterSafeCheck

ZIP Code 92078 Water Quality Report

San Marcos, CA · San Diego County County

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

6

Total Violations

28

Lead Risk

Moderate

Contaminants

1

⚠

Active Water Quality Issues Detected

EPA records show 28 unresolved violations. Contact Vallecitos Water District for current status.

About Tap Water in ZIP Code 92078

Tap water in ZIP code 92078 (San Marcos, CA) meets all federal safety standards and earns a solid B grade (score: 71/100). Served by Vallecitos Water District, the water system has maintained general compliance with EPA Safe Drinking Water Act regulations, with only minor issues on record.

Water System

Vallecitos Water District

EPA ID: CA3710002

Water Source

Surface Water

Population Served

113,500 residents

County

San Diego County County, California

🧪

Lead Levels in ZIP 92078

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

Lead Level: 1.1 ppb — Very Low

The 90th percentile lead level in 92078 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 92078 is rated Moderate. EPA models estimate a 23% 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)
Copper (Consumer Confidence Report)

From annual CCR filing

0.2 ppb
Lead Exposure Risk Rating
Moderate
Lead Exposure Probability

EPA model estimate based on housing age and infrastructure

23%
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

Vallecitos Water District has recorded 6 health-based violations in the past 5 years — significantly above the national average. This volume of violations indicates serious and recurring compliance issues. Independent water testing and in-home filtration are strongly recommended. 28 violations are currently unresolved — meaning the issue has not yet been formally corrected in EPA records. This is a serious concern that residents should follow up on with their water utility.

Total Violations (5 yr)
28
Health-Based Violations
6
Unresolved Violations
28
Boil Water Advisories
0
Compliance Risk
Critical

Regulatory compliance risk is rated Critical — the highest risk category. Vallecitos Water District has an extensive history of unresolved violations and enforcement actions. Independent water testing is highly recommended.

⚗️

Contaminants Detected

Contaminants with health-based violations on record

EPA records identify 1 contaminant associated with health-based violations in ZIP code 92078: Nickel. 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.

Nickel

From Consumer Confidence Report:

Total Dissolved Solids (TDS) (798 ppm); Odor Threshold (32 TON*)

⚖ Enforcement Actions

EPA or state regulators have issued 2 enforcement actions against Vallecitos Water District. Enforcement actions are formal compliance orders or penalties issued when a utility fails to address violations within required timeframes.
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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
Imported water from SDCWA (Northern California and Colorado River) + desalinated water from Claude 'Bud' Lewis Desalination Plant (Carlsbad)
EPA Radon Zone

Lower potential

Zone 3
Energy Burden

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

3.17%

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

🛡 What Should You Do? — ZIP 92078 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Vallecitos Water 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 92078 Water Quality

Is tap water safe to drink in ZIP code 92078?+
Yes — tap water in 92078 (San Marcos, 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 92078 tap water?+
The 90th percentile lead level in 92078 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 92078?+
Tap water in ZIP code 92078 is provided by Vallecitos Water District (EPA ID: CA3710002). This system serves approximately 113,500 residents. You can contact them directly for Consumer Confidence Reports, current advisories, and billing information.
What is the water source for 92078?+
ZIP code 92078 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 92078 have any active water quality violations?+
Yes — there are currently 28 unresolved violations on record for this water system. Unresolved violations indicate issues that have not yet been formally corrected in EPA tracking systems. Contact Vallecitos Water District for the latest update.
How do I get a copy of my water quality report for 92078?+
Your water utility — Vallecitos Water 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 "Vallecitos Water District Consumer Confidence Report." The EPA's ECHO database also has historical compliance data.
What water filter should I use in 92078?+
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 92078, with detected contaminants including Nickel, a multi-stage filter or reverse osmosis system is recommended.
Is 92078 tap water safe for babies and infants?+
Infants are especially vulnerable to lead, nitrates, and microbial contaminants in drinking water. Current EPA data for 92078 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 92078 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 Vallecitos Water 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 →