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

ZIP Code 77391 Water Quality & Testing Report

Spring, TX · Harris County County · Updated for 2026

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 77391 (Spring, TX)?

Yes, tap water in ZIP code 77391 (Spring, TX) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by Montgomery County Municipal Utility District 18, the area earns an EPA Safety Grade of A (95/100) with 0 health violations, 1.0 ppb lead, and very hard (239 mg/L / 14 GPG) water.

Safety Score
A

Water Safety Grade

Excellent — Meets all EPA standards

Health Violations

0

Total Violations

1

Lead Risk

N/A

Contaminants

0

About Tap Water in ZIP Code 77391

Tap water in ZIP code 77391 (Spring, TX) is distributed by Montgomery County Municipal Utility District 18 (EPA ID: TX1700546), serving approximately 7,608 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 95/100.

Water System

Montgomery County Municipal Utility District 18

EPA ID: TX1700546

Water Source

Ground Water

Population Served

7,608 residents

County

Harris County County, Texas

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Lead Levels in ZIP 77391

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

Lead Level: 1.0 ppb — Very Low

The 90th percentile lead level in 77391 is 1.0 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)
1.00 ppb (0.001 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 Hard14 GPG · 239 mg/L

Water in ZIP 77391 is Very Hard (239 mg/L / 14 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

14 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

239 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: Montgomery County Municipal Utility District 18 · PWSID: TX1700546

Verify on EPA.gov
📋

Violation History

Past 5 years — EPA SDWIS data

Montgomery County Municipal Utility District 18 has recorded 1 violation, but none are health-based (e.g., administrative or monitoring infractions).

Total Violations (5 yr)
1
Health-Based Violations
0
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

No health-based contaminant violations are on record for ZIP code 77391 under the Safe Drinking Water Act.

⚖ Enforcement Actions

EPA or state regulators have issued 10 enforcement actions to address compliance lapses.
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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
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 77391

Tap Water & Well Testing Recommendations

Residents in ZIP code 77391 served by Montgomery County Municipal Utility District 18 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 77391 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Montgomery County Municipal Utility District 18
  • ✓ 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 77391 Water Quality

Is tap water safe to drink in ZIP code 77391?+
Yes — tap water in 77391 (Spring, 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 77391 (Spring, TX)?+
To test water quality in ZIP 77391, 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 77391?+
Tap water in 77391 is classified as Very Hard with an estimated mineral hardness of 239 mg/L (14 GPG). A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Should I test private well water in 77391?+
Yes. Unlike municipal systems, private wells in 77391 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 77391 tap water?+
The 90th percentile lead level in 77391 is 1.0 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 77391?+
There are currently no active boil water advisories on record for 77391. Water treatment systems are operating within normal parameters.
Who provides tap water to 77391?+
Tap water in ZIP code 77391 is provided by Montgomery County Municipal Utility District 18 (EPA ID: TX1700546), serving approximately 7,608 residents.
What water filter should I use in 77391?+
Based on water metrics for 77391, we recommend None / Standard Pitcher. Look for certifications such as NSF/ANSI 42 (Chlorine, Taste & Odor).

Data Sources & Methodology

Water quality data for ZIP code 77391 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 Montgomery County Municipal Utility District 18. 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 →