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

ZIP Code 85738 Water Quality & Testing Report

Catalina, AZ · Pima 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 85738 (Catalina, AZ)?

Yes, tap water in ZIP code 85738 (Catalina, AZ) is safe to drink under EPA Safe Drinking Water Act standards. Supplied by Lago Del Oro Water Company, the area earns an EPA Safety Grade of B (70/100) with 0 health violations, 2.7 ppb lead, and very hard (246 mg/L / 14.4 GPG) water.

Safety Score
B

Water Safety Grade

Good — Minor issues on record

Health Violations

0

Total Violations

8

Lead Risk

N/A

Contaminants

0

About Tap Water in ZIP Code 85738

Tap water in ZIP code 85738 (Catalina, AZ) is distributed by Lago Del Oro Water Company (EPA ID: AZ0411117), serving approximately 18,132 residents. Based on EPA Safe Drinking Water Act compliance records, this system receives a water safety grade of B with a composite quality score of 70/100.

Water System

Lago Del Oro Water Company

EPA ID: AZ0411117

Water Source

Ground Water

Population Served

18,132 residents

County

Pima County County, Arizona

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Lead Levels in ZIP 85738

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

Lead Level: 2.7 ppb — Very Low

The 90th percentile lead level in 85738 is 2.7 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)
2.70 ppb (0.0027 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 Hard14.4 GPG · 246 mg/L

Water in ZIP 85738 is Very Hard (246 mg/L / 14.4 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

14.4 GPG
Hardness (PPM / mg/L)

Parts per million CaCO3

246 mg/L
Appliance Scaling Risk
High / Severe

Official EPA SDWIS Database Entry

Utility: Lago Del Oro Water Company · PWSID: AZ0411117

Verify on EPA.gov
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Violation History

Past 5 years — EPA SDWIS data

Lago Del Oro Water Company has recorded 8 violations, but none are health-based (e.g., administrative or monitoring infractions). 6 violations remain unresolved in EPA tracking records.

Total Violations (5 yr)
8
Health-Based Violations
0
Unresolved Violations
6
Boil Water Advisories
0
Compliance Risk
High

Regulatory compliance risk for this utility is rated High 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 85738 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

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 85738

Tap Water & Well Testing Recommendations

Residents in ZIP code 85738 served by Lago Del Oro Water Company 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 Arizona Department of Environmental Quality.
Certified Lab Testing: Always use an EPA-certified drinking water laboratory in AZ for formal legal or real estate compliance testing.

🛡 What Should You Do? — ZIP 85738 Recommendations

  • ✓ Run cold water for 30 seconds each morning before use — especially if pipes are old
  • ✓ Request your annual Consumer Confidence Report from Lago Del Oro Water Company
  • ✓ 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 85738 Water Quality

Is tap water safe to drink in ZIP code 85738?+
Yes — tap water in 85738 (Catalina, AZ) meets EPA standards with a water safety grade of B. No health-based violations are on record in the past 5 years.
How do I get my water tested in ZIP 85738 (Catalina, AZ)?+
To test water quality in ZIP 85738, you can order a certified drinking water test kit or send water samples to an EPA/NELAP certified laboratory in AZ. Certified testing checks for lead, coliform bacteria, nitrates, hardness, and PFAS that standard test strips miss. Contact Arizona Department of Environmental Quality for a list of certified regional labs.
How hard is the tap water in 85738?+
Tap water in 85738 is classified as Very Hard with an estimated mineral hardness of 246 mg/L (14.4 GPG). A whole-home water softener system is strongly recommended to protect plumbing and home appliances.
Should I test private well water in 85738?+
Yes. Unlike municipal systems, private wells in 85738 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 85738 tap water?+
The 90th percentile lead level in 85738 is 2.7 ppb. The EPA action level is 15 ppb. This is below the EPA action level.
Is there an active boil water notice in 85738?+
There are currently no active boil water advisories on record for 85738. Water treatment systems are operating within normal parameters.
Who provides tap water to 85738?+
Tap water in ZIP code 85738 is provided by Lago Del Oro Water Company (EPA ID: AZ0411117), serving approximately 18,132 residents.
What water filter should I use in 85738?+
Based on water metrics for 85738, 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 85738 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 Lago Del Oro Water Company. 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 →