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Official EPA SDWIS Verified ReportWater Quality & Testing GuideStatus: Normal Operations

ZIP Code 78270 Water Quality & Testing Report

San Antonio, TX · Bexar County County · Updated for 2026

Quick EPA Verified Answer

Is Tap Water Safe to Drink in ZIP 78270 (San Antonio, TX)?

Yes, tap water in ZIP code 78270 (San Antonio, TX) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by San Antonio Water System, the area earns an EPA Safety Grade of A (98/100) with 1 health violations, 1.6 ppb lead, and very hard (183 mg/L / 10.7 GPG) water.

Safety Score
A

Water Safety Grade

Excellent — Meets all EPA standards

Health Violations

1

Total Violations

2

Lead Risk

N/A

Contaminants

1

About Tap Water in ZIP Code 78270

Tap water in ZIP code 78270 (San Antonio, TX) is distributed by San Antonio Water System (EPA ID: TX0150018), serving approximately 2,113,151 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of A with a composite quality score of 98/100.

Water System

San Antonio Water System

EPA ID: TX0150018

Water Source

Surface Water

Population Served

2,113,151 residents

County

Bexar County County, Texas

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Lead Levels in ZIP 78270

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

Lead Level: 1.6 ppb — Very Low

The 90th percentile lead level in 78270 is 1.6 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)
1.60 ppb (0.0016 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: Very Hard10.7 GPG · 183 mg/L

Water in ZIP 78270 is Very Hard (183 mg/L / 10.7 GPG). High concentrations of dissolved limestone minerals cause severe mineral buildup, stiff laundry, dry skin, and premature water heater wear.

Recommendation: A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Hardness (GPG)

Grains per gallon

10.7 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

183 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: San Antonio Water System · PWSID: TX0150018

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

San Antonio Water System has recorded 1 health-based violation out of 2 total violations over the past 5 years.

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

Regulatory compliance risk for this utility is rated Moderate 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: Stage 1 DBP Rule.

Stage 1 DBP Rule

From Consumer Confidence Report:

Trihalomethane (TTHM) (52.9 ppb)

⚖ Enforcement Actions

EPA or state regulators have issued 10 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
CCR Source Classification
Surface Water and Ground Water
EPA Radon Zone

Lower potential

Zone 3

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

Water Quality Testing in ZIP 78270

Tap Water & Well Testing Recommendations

Residents in ZIP code 78270 served by San Antonio Water System 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 Texas Commission on Environmental Quality (TCEQ).
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in TX for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 78270 Recommendations

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

Recommended Taste & Safety Filter:

🚰

NSF/ANSI 53 Certified Pitcher Filter

Best for removing aesthetic chlorine, odors, and low-level heavy metals.

Filter Selection Guide →

Frequently Asked Questions — ZIP 78270 Water Quality

Is tap water safe to drink in ZIP code 78270?+
Yes — tap water in 78270 (San Antonio, TX) meets EPA standards with a water safety grade of A. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 78270 (San Antonio, TX)?+
To test water quality in ZIP 78270, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in TX. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact Texas Commission on Environmental Quality (TCEQ) for a list of certified regional labs.
How hard is the tap water in 78270?+
Tap water in 78270 is classified as Very Hard with an estimated mineral hardness of 183 mg/L (10.7 GPG). A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Should I test private well water in 78270?+
Yes. Unlike municipal systems, private wells in 78270 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 78270 tap water?+
The 90th percentile lead level in 78270 is 1.6 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 78270?+
There are currently no active boil water advisories on record for 78270. Water treatment systems are operating within normal parameters.
Who provides tap water to 78270?+
Tap water in ZIP code 78270 is provided by San Antonio Water System (EPA ID: TX0150018), serving approximately 2,113,151 residents.
What water filter should I use in 78270?+
Based on water metrics for 78270, 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 78270 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 Antonio Water System. 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 →