WaterVerge

Is Vaya Chin, Hickiwan, San Simon Village/S, AZ Tap Water Safe to Drink?

Graded A- — but Chromium-6, Vanadium and 1 more were detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓

1K residents served 1 water system PWSID: 090400020
Overall Score
87.5 / 100
Violations
1 active
Last Updated
May 2026
Source
Groundwater
#76 of 292 in Arizona Top 26% nationally
Native American
High data confidence
Reviewed by WaterVerge Editorial Team · Last updated May 2026
A-GRADE
Water Quality Grade
87.5/100
waterverge.com
A- 87.5/100

Vaya Chin, Hickiwan, San Simon Village/S, AZ — Water Quality Report

Vaya Chin, Hickiwan, San Simon Village/S's drinking water received a grade of A- (87.5 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,151 residents using groundwater.

Lead levels were measured at 0.5 ppb (90th percentile), well within EPA limits. UCMR 5 testing detected 1 PFAS compound in the water supply.

The system has 12 violations on record, including 1 health-based violation. 1 remains unresolved.

Data last updated: May 2026 · Source: EPA SDWIS, UCMR 5
Analysis

What to know about Vaya Chin, Hickiwan, San Simon Village/S's water

Vaya Chin, Hickiwan, San Simon Village/S ranks #76 out of 292 cities in Arizona for water quality, placing it mid-range in the state.

Vaya Chin, Hickiwan, San Simon Village/S 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.

PFAS compounds were detected in testing, though levels remain within current EPA limits. Residents seeking extra precaution may consider an activated carbon or reverse osmosis filter.

Hexavalent chromium (chromium-6) was detected at 25.10 µg/L, above California's 10 µg/L limit. There is no federal MCL, but the EPA is reviewing evidence linking long-term exposure to cancer risk.

As a small community water system, Vaya Chin, Hickiwan, San Simon Village/S may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.

Quality Breakdown

Water quality score

See methodology →
87.5 out of 100 Grade A-
A: 90-100
B: 74-89
C: 60-73
F: <50
How is this calculated?
Violations
40.4/45
B
Historical violation record including health-based and monitoring violations.
Lead & Copper
20/20
A
Lead at 0.5 ppb (90th percentile).
Contaminants
14.2/20
C
1 PFAS compound detected.
Compliance
8/10
B
Monitoring and reporting compliance with EPA regulations.
Source Risk
5/5
A
Water source: Groundwater.
Water Safety

Is Vaya Chin, Hickiwan, San Simon Village/S, AZ water safe to drink?

Use Caution

Vaya Chin, Hickiwan, San Simon Village/S's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (87.5/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,151 residents using groundwater (wells).

1
Active Violations
0.5 ppb
Lead (90th %ile)
1 compound
PFAS Detected
9 events
Disaster History

Recent water quality updates for Vaya Chin, Hickiwan, San Simon Village/S

A timeline of significant water quality events, violations, and data updates.

PFAS
1 PFAS "forever chemical" compound detected

Detected at levels within current EPA limits. PFAS persist indefinitely in the environment.

Update
Water quality data updated

Latest EPA compliance and testing data incorporated into Vaya Chin, Hickiwan, San Simon Village/S's water quality assessment. Grade: A- (87.5/100).

Violation
1 drinking water violation recorded

Contaminants: Nitrate.

Violation
2 drinking water violations recorded

Contaminants: TTHM, Total Haloacetic Acids (HAA5).

Violation
2 drinking water violations recorded

Contaminants: Total Haloacetic Acids (HAA5), TTHM.

Disaster
HURRICANE KATRINA EVACUATION

Federal disaster declaration (FEMA DR-3241). Hurricane event — may have impacted local water infrastructure.

Key contaminant findings

Based on the most recent EPA sampling data for Vaya Chin, Hickiwan, San Simon Village/S's water supply.

Lead Within Limits
Detected: 0.5 ppb Limit: 15 ppb (EPA Action Level)

Well within EPA limits.

PFAS (1 compound) Elevated
Detected: Highest: lithium at 24.0000 µg/L Limit: 0.004 µg/L (EPA MCL)

Detected but within current EPA limits. PFAS do not break down in the environment and can accumulate in the body over time. An activated carbon filter can reduce exposure.

Chromium-6 (Hexavalent Chromium) Exceeds Limit
Detected: 25.10 µg/L Limit: 10 µg/L (California MCL — no federal limit)

The "Erin Brockovich" chemical. There is no federal MCL, but California has set a limit of 10 µg/L. Reverse osmosis filtration is effective at removing hexavalent chromium.

Violation history

Vaya Chin, Hickiwan, San Simon Village/S's water system has 12 total violations on record, including 1 health-based violation. 1 remain unresolved. 3 violations were issued in the last 5 years.

MRMCL
Most recent violations:
Jan 2025 Nitrate Resolved
Jan 2023 TTHM Resolved
Jan 2023 Total Haloacetic Acids (HAA5) Resolved
Jan 2014 Total Haloacetic Acids (HAA5) Resolved
Jan 2014 TTHM Resolved

Flood & environmental risk

Pima County has experienced 9 federally declared disasters since 1966. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.

HURRICANE KATRINA EVACUATION
Hurricane FEMA DR-3241
SEVERE STORMS, TORNADOES & FLOODING
Flood FEMA DR-977
SEVERE STORMS & FLOODING
Flood FEMA DR-884

Where does Vaya Chin, Hickiwan, San Simon Village/S's water come from?

Vaya Chin, Hickiwan, San Simon Village/S's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,151 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.

What Vaya Chin, Hickiwan, San Simon Village/S residents can do

Request your utility's CCR

Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.

Monitor alerts during storms

Vaya Chin, Hickiwan, San Simon Village/S's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.

Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.

Contaminant Alerts

Top contaminants to know

View all ↓
Lead (90th percentile)
Inorganic / Heavy Metal
Safe
0.5 ppb
EPA Action Level: 15 ppb · 3% of limit
Safe Level
lithium
PFAS / Forever Chemical
Near MCL
24.0000 µg/L
EPA MCL: 0.004 µg/L · +20% over limit
Detected
Chromium-6 (Hexavalent Chromium)
Inorganic
Over CA Limit
25.10 µg/L
CA MCL (no federal MCL): 10 µg/L · +20% over limit
Over CA MCLUCMR 3 Data
Strontium
Inorganic
Detected
148.0 µg/L
EPA Health Ref Level: 1,500 µg/L · 10% of limit
DetectedUCMR 3 Data
Vanadium
Inorganic
Over HA
37.00 µg/L
EPA Short-term HA: 21 µg/L · +20% over limit
Over Health AdvisoryUCMR 3 Data
Chlorate
Disinfection Byproduct
Over HA
360.0 µg/L
EPA Lifetime HA: 210 µg/L · +20% over limit
Over Health AdvisoryUCMR 3 Data
Molybdenum
Inorganic
Detected
5.00 µg/L
EPA Lifetime HA: 40 µg/L · 13% of limit
DetectedUCMR 3 Data
Lithium
Inorganic
Detected
24.0 µg/L
State screening level: 60 µg/L · 40% of limit
DetectedNo federal MCLUCMR 5 Data (2023–2025)
PFAS Testing

Forever chemicals overview

National PFAS report →
30
Compounds tested
1
Detected
0
Exceed EPA MCL
Compliance Record

Violation summary

12
Total violations
1
Health-based
1
Active / unresolved
Jan 2025
Most recent violation
Compliance Record

Violations & advisories

12 Total
1 Active
1 Health-based
11 Resolved
2 SNC
Violations by category
Stage 2 Disinfectants and Disinfection Byproducts Rule
4
Total Coliform Rule
4
Nitrate Rule
2
Radionuclides and Revised Rad Rule
1
Active
Compliance Violation
Monitoring 0
Jan 2025 Resolved
Nitrate
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2025
Jan 2023 Resolved
TTHM
Monitoring & Reporting
SNC Monitoring & Reporting Resolved Dec 2025
Jan 2023 Resolved
Total Haloacetic Acids (HAA5)
Monitoring & Reporting
SNC Monitoring & Reporting Resolved Dec 2025
Jan 2014 Resolved
Total Haloacetic Acids (HAA5)
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2014
Jan 2014 Resolved
TTHM
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2014
May 2008 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved May 2008
Apr 2008 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved Apr 2008
Jan 2004 Resolved
Gross Alpha, Excl. Radon and U
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2004
Jan 2004 Resolved
Nitrate
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2004
Oct 2003 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved Oct 2003
Oct 2001 Resolved
Coliform (TCR)
Max Contaminant Level
Health-Based Health Resolved Oct 2001
Environmental Risk

Flood & disaster history

9
Declared disasters
Sep 2005
Most recent
Flood
Most common type

Pima County has experienced 9 federally declared disasters since 1966. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.

Sep 2005
HURRICANE KATRINA EVACUATION
Hurricane FEMA #3241
Jan 1993
SEVERE STORMS, TORNADOES & FLOODING
Flood FEMA #977
Dec 1990
SEVERE STORMS & FLOODING
Flood FEMA #884
Oct 1983
SEVERE STORMS & FLOODING
Flood FEMA #691
Dec 1978
SEVERE STORMS & FLOODING
Flood FEMA #570
Mar 1978
SEVERE STORMS & FLOODING
Flood FEMA #551

Recommended water filters

Based on contaminants detected in Vaya Chin, Hickiwan, San Simon Village/S's water supply, we recommend the following filter types.

🧪
For PFAS
Reverse Osmosis or Activated Carbon Block
1 PFAS compound detected

Full contaminants report

Contaminant Detected Level EPA Limit Unit Category Status
Lead (90th percentile) 0.5 15 ppb Inorganic Safe
11Cl-PF3OUdS ND HI µg/L PFAS Not Detected
4:2 FTS ND HI µg/L PFAS Not Detected
6:2 FTS ND HI µg/L PFAS Not Detected
8:2 FTS ND HI µg/L PFAS Not Detected
9Cl-PF3ONS ND HI µg/L PFAS Not Detected
ADONA ND HI µg/L PFAS Not Detected
HFPO-DA ND 0.01 µg/L PFAS Not Detected
lithium 24.000 HI µg/L PFAS Detected
NEtFOSAA ND HI µg/L PFAS Not Detected
NFDHA ND HI µg/L PFAS Not Detected
NMeFOSAA ND HI µg/L PFAS Not Detected
PFBA ND HI µg/L PFAS Not Detected
PFBS ND HI µg/L PFAS Not Detected
PFDA ND HI µg/L PFAS Not Detected
PFDoA ND HI µg/L PFAS Not Detected
PFEESA ND HI µg/L PFAS Not Detected
PFHpA ND HI µg/L PFAS Not Detected
PFHpS ND HI µg/L PFAS Not Detected
PFHxA ND HI µg/L PFAS Not Detected
PFHxS ND HI µg/L PFAS Not Detected
PFMBA ND HI µg/L PFAS Not Detected
PFMPA ND HI µg/L PFAS Not Detected
PFNA ND HI µg/L PFAS Not Detected
PFOA ND 0.004 µg/L PFAS Not Detected
PFOS ND 0.004 µg/L PFAS Not Detected
PFPeA ND HI µg/L PFAS Not Detected
PFPeS ND HI µg/L PFAS Not Detected
PFTA ND HI µg/L PFAS Not Detected
PFTrDA ND HI µg/L PFAS Not Detected
PFUnA ND HI µg/L PFAS Not Detected
Data source: EPA SDWIS, UCMR 5, local utility CCR.

Lead level trend (90th percentile)

EPA action level: 15 ppb
Lead has decreased by 4.5 ppb from 1994 (5.0 ppb) to 2025 (0.5 ppb).
Contaminant Rankings

See how Vaya Chin, Hickiwan, San Simon Village/S compares by contaminant

Explore where Vaya Chin, Hickiwan, San Simon Village/S ranks among all Arizona cities for specific contaminants.

Infrastructure

Water source & infrastructure

Primary Source
Groundwater
Operator
Native American
Population Served
1,151
Water Systems
1
Water Source

Where Vaya Chin, Hickiwan, San Simon Village/S's water comes from

Groundwater

Vaya Chin, Hickiwan, San Simon Village/S's drinking water is drawn from underground aquifers through wells.

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 1,151 people through 1 water system.

Infrastructure

Water systems serving Vaya Chin, Hickiwan, San Simon Village/S

System Name PWSID Population Source
Vaya Chin Intertie 090400020 1,151 GW
Regional Comparison

How Vaya Chin, Hickiwan, San Simon Village/S compares

Full Arizona rankings →

Vaya Chin, Hickiwan, San Simon Village/S's score of 87.5/100 is above the average of 42/100 among major Arizona cities. It outscores 10 of 10 nearby cities.

Vaya Chin, Hickiwan, San Simon Village/S (this city)
87.5
Phoenix
37.5
Tucson
38.1
Mesa
40.6
Chandler
40.5
Gilbert
34.8
Arizona avg
42
City Profile

About Vaya Chin, Hickiwan, San Simon Village/S, AZ

Wikipedia →

Sells is an unincorporated community and census-designated place (CDP) in Pima County, Arizona, United States. The population was 2,799 at the 2000 census. It is the capital of the Tohono O'odham Nation and the home of several tribal businesses, such as Tohono O'Odham Ki:Ki Association. It was originally named Indian Oasis by cattle-ranchers/businessmen brothers Joseph and Louis Ménager in 1912. The Ménager brothers also built and ran the Indian Oasis Mercantile Store. The settlement took its present English name in 1918 to honor Indian Commissioner Cato Sells. The O'odham name means "tortoise got wedged".

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Frequently asked questions

Is Vaya Chin, Hickiwan, San Simon Village/S, AZ tap water safe to drink?

Vaya Chin, Hickiwan, San Simon Village/S's water quality earned a grade of A- (87.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #76 out of 292 cities tested in Arizona.

What contaminants are in Vaya Chin, Hickiwan, San Simon Village/S's water?

Lead was measured at 0.5 ppb (90th percentile). 1 PFAS compound was detected. 12 violations are on record.

How is Vaya Chin, Hickiwan, San Simon Village/S'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 Vaya Chin, Hickiwan, San Simon Village/S?

PFAS compounds have been detected. A filter with activated carbon can help reduce exposure.

Where does Vaya Chin, Hickiwan, San Simon Village/S's water come from?

Vaya Chin, Hickiwan, San Simon Village/S's water is sourced from Groundwater. The city has 1 water system serving approximately 1,151 residents.

What health violations has Vaya Chin, Hickiwan, San Simon Village/S's water system had?

Vaya Chin, Hickiwan, San Simon Village/S has 1 health-based violation on record. The most recent violation was recorded in January 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.

Is Vaya Chin, Hickiwan, San Simon Village/S's groundwater at risk of contamination?

Vaya Chin, Hickiwan, San Simon Village/S 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 12 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 Vaya Chin, Hickiwan, San Simon Village/S's water compare to other cities?

Vaya Chin, Hickiwan, San Simon Village/S ranks #76 out of 292 cities in Arizona (better than 74% of state cities) and #4031 out of 15744 cities nationally (74th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.

Does Vaya Chin, Hickiwan, San Simon Village/S's small water system affect quality?

Vaya Chin, Hickiwan, San Simon Village/S's system serves approximately 1,151 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 12 violations on record.