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Official EPA SDWIS Verified ReportWater Quality & Testing GuideHistorical Record: No Recorded SDWIS Violations

ZIP Code 94139 Water Quality & Testing Report

San Francisco, CA · San Francisco County County · Updated for 2026

Sahajul HaqueCompiled & verified by Sahajul Haque from official EPA SDWIS records
Public Health & Medical Notice: Drinking water quality data on this page reflects historical compliance records submitted under the Safe Drinking Water Act. This information does not constitute medical advice or a real-time safety guarantee. If you are pregnant, nursing, preparing infant formula, or immunocompromised, consult a healthcare provider. Boiling water kills biological pathogens, but does NOT remove chemical contaminants like lead, arsenic, or PFAS.
Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 94139 (San Francisco, CA)?

Caution / Filtration Recommended: Tap water in ZIP code 94139 (San Francisco, CA) has compliance concerns, earning an EPA Safety Grade of D (53/100) due to 6 health violation(s) and 3.1 ppb lead. While treated by Presidio of San Francisco, residents are advised to use an NSF/ANSI 53 certified water filter for drinking and cooking.

Safety Score
D

Water Safety Grade

Poor — Multiple violations recorded

Health Violations

6

Total Violations

7

Lead Risk

N/A

Contaminants

1

⚠

Active Water Quality Issues Detected

EPA records show 7 unresolved violations. Contact Presidio of San Francisco for current status.

About Tap Water in ZIP Code 94139

Tap water in ZIP code 94139 (San Francisco, CA) is distributed by Presidio of San Francisco (EPA ID: CA3810700), serving approximately 3,500 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of D with a composite quality score of 53/100.

Water System

Presidio of San Francisco

EPA ID: CA3810700

Water Source

Surface Water

Population Served

3,500 residents

County

San Francisco County County, California

🧪

Lead Levels in ZIP 94139

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

Lead Level: 3.1 ppb — Very Low

The 90th percentile lead level in 94139 is 3.1 ppb. This meets the EPA action level of 15 ppb. Health experts recommend a target of 0 ppb for optimal safety.
Lead Level (90th percentile)
3.10 ppb (0.0031 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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Water Hardness & Mineral Content

Grains per gallon (GPG) & Parts per million (PPM / mg/L)

Classification: Hard8 GPG · 137 mg/L

Water in ZIP 94139 is Hard (137 mg/L / 8 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

8 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

137 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: Presidio of San Francisco · PWSID: CA3810700

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Presidio of San Francisco has recorded 6 health-based violations out of 7 total violations over the past 5 years. 7 violations remain unresolved in EPA tracking records.

Total Violations (5 yr)
7
Health-Based Violations
6
Unresolved Violations
7
Boil Water Advisories
0
Compliance Risk
Critical

Regulatory compliance risk for this utility is rated Critical based on past reporting and enforcement records.

⚗️

Contaminants Detected

Contaminants with health-based violations on record

EPA records identify 1 contaminant with health-based violations in the past 5 years: Contaminant 0700.

Contaminant 0700

⚖ Enforcement Actions

EPA or state regulators have issued 4 enforcement actions to address compliance lapses.
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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
EPA Radon Zone

Moderate potential

Zone 2

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

Water Quality Testing in ZIP 94139

Tap Water & Well Testing Recommendations

Residents in ZIP code 94139 served by Presidio of San Francisco 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 94139 Recommendations

  • 🚨 Install a certified NSF/ANSI 53 or 58 (reverse osmosis) filter immediately for drinking and cooking
  • 🚨 Do not give unfiltered water to children, pregnant women, or immunocompromised individuals
  • 🚨 Contact Presidio of San Francisco to request the current violation status and corrective action plan
  • 🚨 Report concerns to your state environmental agency or call the EPA hotline: 1-800-426-4791
  • 🚨 Consider having your home's tap water independently tested by a certified lab

Recommended Water Treatment Systems:

REQUIRED FOR SAFETY
🏺

NSF 53 Lead Pitcher Filter

Certified to remove lead. Recommended for immediate protection.

Lead Filter Guide →
STRONGLY RECOMMENDED
⚗️

NSF 58 Under-Sink RO System

Reverse Osmosis system certified to remove PFAS, heavy metals, and viruses.

RO System Guide →

Frequently Asked Questions — ZIP 94139 Water Quality

Is tap water safe to drink in ZIP code 94139?+
Tap water in 94139 has a below-average safety grade of D due to compliance issues. We recommend using a certified water filter for drinking and cooking.
How do I get my water tested in ZIP 94139 (San Francisco, CA)?+
To test water quality in ZIP 94139, 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 94139?+
Tap water in 94139 is classified as Hard with an estimated mineral hardness of 137 mg/L (8 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 94139?+
Yes. Unlike municipal systems, private wells in 94139 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 94139 tap water?+
The 90th percentile lead level in 94139 is 3.1 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 94139?+
There are currently no active boil water advisories on record for 94139. Water treatment systems are operating within normal parameters.
Who provides tap water to 94139?+
Tap water in ZIP code 94139 is provided by Presidio of San Francisco (EPA ID: CA3810700), serving approximately 3,500 residents.
What water filter should I use in 94139?+
Based on water metrics for 94139, we recommend Reverse Osmosis (PFAS & Lead). Look for certifications such as NSF/ANSI 53 (Chemical Contaminants), NSF/ANSI 42 (Aesthetic Effects).

Data Sources & Methodology

Water quality data for ZIP code 94139 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 Presidio of San Francisco. 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 →