Public water system record
Tonto Hills DWID
Serves an area of Maricopa County, AZ · 350 people served
Federal records show no health-based violations and 21 monitoring/reporting issues for Tonto Hills DWID in the last ten years. At least one of these issues remains unresolved.
System profile
- Health-based violations, last 10 years
- 0
- Resolved
- 0
- Unresolved
- 0
- Any acute record
- No
- Monitoring issues, last 10 years
- 21
Key facts
- Tonto Hills DWID buys its water from City of Scottsdale.
- Most recent formal enforcement: consent decree or court judgment by Arizona, April 1981.
- Record on file since 1978, with 6 health-based violations before October 19, 2016.
- Lead pipe inventory: 0 lead and 49 unknown out of 144 service lines.
Check whether Tonto Hills DWID serves your address
Health-based violations
Since October 2016Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.
None since October 2016.
Monitoring and reporting issues
Since October 2016Missed tests or reports, not contaminants found above a limit.
| Issue | Start date | Status |
|---|---|---|
|
Public Notice
OTHER
|
Aug 14, 2025 | Active |
|
Revised Total Coliform Rule
RPT
|
Jul 1, 2025 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Jun 1, 2025 |
Archived
Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.
|
|
Surface Water Treatment Rule
Monitoring and reporting
|
Oct 1, 2024 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Sep 1, 2024 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Jul 1, 2024 | Resolved |
|
Lead and Copper Rule
Monitoring and reporting
|
Jul 1, 2024 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Oct 1, 2023 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Sep 1, 2023 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Aug 1, 2023 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Jul 1, 2023 | Resolved |
|
Lead and Copper Rule
Monitoring and reporting
|
Jul 1, 2023 | Resolved |
|
Chlorine
Monitoring and reporting
|
Apr 1, 2023 | Resolved |
|
Chlorine
Monitoring and reporting
|
Jul 1, 2022 | Resolved |
|
Surface Water Treatment Rule
Monitoring and reporting
|
Jul 1, 2022 | Resolved |
|
Chlorine
Monitoring and reporting
|
Jul 1, 2021 | Resolved |
|
Chlorine
Monitoring and reporting
|
Apr 1, 2021 | Resolved |
|
Lead and Copper Rule
Monitoring and reporting
|
Jan 1, 2020 | Resolved |
|
Haloacetic Acids (HAA5)
Monitoring and reporting
|
Apr 1, 2017 | Resolved |
|
Total Trihalomethanes (TTHMs)
Monitoring and reporting
|
Apr 1, 2017 | Resolved |
|
Chlorine
Monitoring and reporting
|
Jan 1, 2017 | Resolved |
Full record since 1978
EPA's records for Tonto Hills DWID go back to 1978. Before October 19, 2016 they list 6 health-based violations (4 resolved, 2 archived by EPA without a recorded fix) and 125 monitoring or reporting violations.
| Violations that began in | Health-based | Monitoring and reporting |
|---|---|---|
| 1970s | 0 | 9 |
| 1980s | 2 | 19 |
| 1990s | 0 | 52 |
| 2000s | 3 | 29 |
| 2010 to October 18, 2016 | 1 | 16 |
| October 19, 2016 to 2019 | 0 | 3 |
| 2020s | 0 | 18 |
Most recent health-based violation before October 19, 2016: Total Coliform, began January 2014, Resolved.
Show all 6 health-based violations before October 19, 2016
| Contaminant | Start date | Status |
|---|---|---|
|
Total Coliform
Contaminant limit exceeded
|
Jan 1, 2014 | Resolved |
|
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.096 mg/L, federal limit 0.08 mg/L (1.2 times the limit)
|
Jan 1, 2006 | Resolved |
|
Combined Radium (-226 and -228)
Contaminant limit exceeded
Measured 10.4 pCi/L, federal limit 5 pCi/L (2.1 times the limit)
|
May 1, 2002 | Resolved |
|
Gross Alpha, Excl. Radon and U
Contaminant limit exceeded
Measured 27 pCi/L, federal limit 15 pCi/L (1.8 times the limit)
|
May 1, 2002 | Resolved |
|
Fluoride
Contaminant limit exceeded
|
Apr 8, 1981 | Archived |
|
Fluoride
Contaminant limit exceeded
|
Feb 11, 1981 | Archived |
Enforcement actions
Arizona regulators took 1 formal enforcement action against Tonto Hills DWID in 1981. The most recent was a consent decree or court judgment in April 1981.
| Date | By | Action | Violations covered |
|---|---|---|---|
| Apr 30, 1981 | Arizona | Consent decree or court judgment | 1 violation (1 health-based): Fluoride |
Where the water comes from
Tonto Hills DWID buys its water from City of Scottsdale. It lists no wells or intakes of its own.
Buys water from
- City of Scottsdale Scottsdale, AZ
Annual water quality report
Tonto Hills DWID must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.
Systems serving 500 or fewer people may meet the rule by telling customers the report is available on request, so you may need to ask Tonto Hills DWID for a copy.
Find a posted report with EPA's Consumer Confidence Report search
Testing your own water
To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by Arizona.
Certified drinking water labs by state EPA guidance for private wells