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WaterVerge

Water quality report · updated Jul 2026

Is Casamero Lake, Borrego Pass, Smith Lake, AZ Tap Water Safe to Drink?

Graded A, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do ↓

0 contaminants over a legal limit
2.5 ppb lead, 90th percentile · low
4 unresolved violations
906 people served by 1 water system

PWSID NN3500256 · moderate data confidence · native american utility

Reviewed by WaterVerge Editorial Team · Last updated July 2026
A 91.9 / 100

#37 of 271Arizona cities
How we grade →

01The verdict: is Casamero Lake, Borrego Pass, Smith Lake water safe?

Casamero Lake, Borrego Pass, Smith Lake's drinking water has significant quality concerns based on EPA testing data. With a grade of A (91.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 906 residents using groundwater (wells).

The concern

4 unresolved violations on record

EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.

See what was cited ↓
The good news

Lead is well under the limit

90th-percentile lead is 2.5 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.

See the trend ↓
Keep watching

A flood-prone service area

6 federal disaster declarations on record. After severe weather, watch for boil-water advisories.

See the risk factors ↓

Casamero Lake, Borrego Pass, Smith Lake's drinking water received a grade of A (91.9 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 906 residents using groundwater.

Lead levels were measured at 2.5 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 86 violations on record, including 2 health-based violations. 4 remain unresolved.

Casamero Lake, Borrego Pass, Smith Lake ranks #37 out of 271 cities in Arizona for water quality, placing it above average in the state. Casamero Lake, Borrego Pass, Smith Lake relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. As a small community water system, Casamero Lake, Borrego Pass, Smith Lake may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.

How the 91.9/100 breaks down Methodology →
ViolationsHistorical violation record including health-based and monitoring violations.
39.9 / 45B
Lead & CopperLead at 2.5 ppb (90th percentile).
20 / 20A
ContaminantsPFAS + legacy contaminant analysis.
17 / 20B
ComplianceMonitoring and reporting compliance with EPA regulations.
10 / 10A
Source RiskWater source: Groundwater.
5 / 5A

02What's in Casamero Lake, Borrego Pass, Smith Lake's water

Every contaminant flagged in Casamero Lake, Borrego Pass, Smith Lake, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.

1 detection · sorted by % of legal limit
Over the limit Elevated — watch Within limits
0 50% LEGAL LIMIT 150%
1 contaminant tested under EPA SDWIS, LCR and UCMR programs · 1 detected · not yet tested for PFAS under UCMR 5

Full contaminants report

Contaminant Detected Level EPA Limit Unit Category Status
Lead (90th percentile) 2.5 15 ppb Inorganic Safe
Data source: EPA SDWIS, UCMR 5, local utility CCR.

03Casamero Lake, Borrego Pass, Smith Lake's ten-year track record

Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 86 violations on record, including 2 health-based violations. 4 remain unresolved.

All ten of the last ten years were clean — no EPA violations recorded for Casamero Lake, Borrego Pass, Smith Lake.

UpdateWater quality data updatedLatest EPA compliance and testing data incorporated into Casamero Lake, Borrego Pass, Smith Lake's water quality assessment. Grade: A (91.9/100).
DisasterSEVERE STORMS AND FLOODINGFederal disaster declaration (FEMA DR-4620). Flood event — may have impacted local water infrastructure.
Violation1 drinking water violation recordedContaminants: Revised Total Coliform Rule.Open
Violation4 drinking water violations recordedContaminants: Diquat, Glyphosate, Endothall.Resolved
Violation6 drinking water violations recorded1 health-based. Contaminants: 2,3,7,8-TCDD, Glyphosate, Endothall.Open
DisasterHURRICANE KATRINA EVACUATIONFederal disaster declaration (FEMA DR-3241). Hurricane event — may have impacted local water infrastructure.
Lead, 90th percentileppb · lower is better
05101520EPA action level · 15 ppb1993 — 2 ppb1994 — 1 ppb1995 — 2 ppb2001 — 4.8 ppb2004 — 1 ppb2007 — 6 ppb2010 — 1 ppb2013 — 1 ppb2016 — 2 ppb2019 — 1 ppb2022 — 2.5 ppb22.519932001201020192022

Up 0.50 ppb since 1993. Latest reading: 2.5 ppb (2022) — 17% of the action level. Sampled at higher-risk homes (90th percentile).

04Where Casamero Lake, Borrego Pass, Smith Lake's water comes from

Casamero Lake, Borrego Pass, Smith Lake's drinking water is drawn from underground aquifers through wells.

Source

Groundwater

Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.

Treatment

Local treatment

Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.

Distribution

1 system

1 water system (1 wholesaler), operated under native american ownership.

Delivery

906 people

Residents served across Casamero Lake, Borrego Pass, Smith Lake's service area.

Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by native american ownership and serves approximately 906 people through 1 water system.

System namePWSIDPopulationSource
Casamero Lake-Smith Lake NTUA NN3500256 906 Groundwater

05Pressure on Casamero Lake, Borrego Pass, Smith Lake's watershed

Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.

Flood & storm history

Recurring — declared disasters

6 federal disaster declarations on record for Apache County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.

SEVERE STORMS AND FLOODING Sep 2021 · DR-4620
HURRICANE KATRINA EVACUATION Sep 2005 · DR-3241
SEVERE STORMS, TORNADOES & FLOODING Jan 1993 · DR-977

06How Casamero Lake, Borrego Pass, Smith Lake compares

Scores for nearby Arizona cities on one line, with the average marked.

Casamero Lake, Borrego Pass, Smith Lake (this city)
91.9 · A
Mesa
40.6 · F
Chandler
40.5 · F
Tucson
38.1 · F
Phoenix
37.5 · F
Gilbert
34.8 · F

dashed line = Arizona average (41/100)

Casamero Lake, Borrego Pass, Smith Lake scores 91.9/100above the Arizona average of 41/100. It outscores 10 of 10 nearby cities. Full Arizona rankings →

07What to do at home

Steps matched to what testing actually found in Casamero Lake, Borrego Pass, Smith Lake's water — not generic advice.

Extra protection

A basic carbon filter still helps

Casamero Lake, Borrego Pass, Smith Lake's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.

Compare tested filters →
Know your report

Read your utility's annual report

Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.

How to read a CCR →
Stay informed

Watch for Casamero Lake, Borrego Pass, Smith Lake alerts

This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.

All water alerts →

Frequently asked questions

Is Casamero Lake, Borrego Pass, Smith Lake, AZ tap water safe to drink?

Casamero Lake, Borrego Pass, Smith Lake's water quality earned a grade of A (91.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #37 out of 271 cities tested in Arizona.

What contaminants are in Casamero Lake, Borrego Pass, Smith Lake's water?

Lead was measured at 2.5 ppb (90th percentile). 86 violations are on record.

How is Casamero Lake, Borrego Pass, Smith Lake's water quality grade calculated?

The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.

Do I need a water filter in Casamero Lake, Borrego Pass, Smith Lake?

Based on current data, basic filtration should suffice for additional peace of mind.

Where does Casamero Lake, Borrego Pass, Smith Lake's water come from?

Casamero Lake, Borrego Pass, Smith Lake's water is sourced from Groundwater. The city has 1 water system serving approximately 906 residents.

What health violations has Casamero Lake, Borrego Pass, Smith Lake's water system had?

Casamero Lake, Borrego Pass, Smith Lake has 2 health-based violations on record. The most recent violation was recorded in April 2016. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.

Is Casamero Lake, Borrego Pass, Smith Lake's groundwater at risk of contamination?

Casamero Lake, Borrego Pass, Smith Lake uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 86 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.

How does Casamero Lake, Borrego Pass, Smith Lake's water compare to other cities?

Casamero Lake, Borrego Pass, Smith Lake ranks #37 out of 271 cities in Arizona (better than 86% of state cities) and #1450 out of 15382 cities nationally (91th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.

Does Casamero Lake, Borrego Pass, Smith Lake's small water system affect quality?

Casamero Lake, Borrego Pass, Smith Lake's system serves approximately 906 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 86 violations on record.

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About Casamero Lake, Borrego Pass, Smith Lake, AZ: Window Rock, known in Navajo as Tségháhoodzání, is a city and census-designated place that serves as the capital of the Navajo Nation, the largest Native American tribe by both land and tribal enrollment. The capital lies within the boundaries of the St. Michaels Chapter, adjacent to the Arizona and New Mexico state line. Window Rock is the site of the Navajo Nation governmental campus, which contains the Navajo Nation Council, Navajo Nation Supreme Court, the offices of the Navajo Nation President and Vice President, and many Navajo government buildings. Wikipedia → Sources: EPA SDWIS & ECHO · UCMR 3–5 · Lead & Copper Rule samples · EPA TRI · U.S. Drought Monitor · FEMA declarations. Data last updated Jul 2026. Analysis by the WaterVerge Editorial Team · methodology.