City of Thornton

Published drinking-water records and contacts for City of Thornton. System CO0101150. Review sources and dates; not a real-time water assessment.

System ID: CO0101150
State or territory: CO
Published population served: 226465
System type (source code): CWS

Published records and dates

PFAS / lithium (EPA UCMR 5): 210 — 2023-02-14 – 2023-11-27
Lead and copper monitoring summaries: 27 — 1992-07-01 – 2025-12-31

Missing records here do not mean the provider did not test. Published records are not a real-time assessment of your tap water.

Read the provider’s annual water quality report

Report link listed: 2026-10-05. This is not the report’s sampling date.

Published testing results

Selected recent records are shown below. Different sampling locations and dates are not interchangeable. These excerpts are not a complete testing history.

“<” means below the stated reporting limit, not zero. A reported measurement alone is not a safety verdict. Read an example

EPA UCMR 5 — most recent imported sample per substance
Substance	Published result	Reporting limit	Sample date	Sampling location
11Cl-PF3OUdS	< 0.005 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
4:2 FTS	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
6:2 FTS	< 0.005 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
8:2 FTS	< 0.005 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
9Cl-PF3ONS	< 0.002 µg/L	0.002 µg/L	2023-11-27	Thornton Treatment Plant / 022
ADONA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
HFPO-DA	< 0.005 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
NEtFOSAA	< 0.005 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
NFDHA	< 0.02 µg/L	0.02 µg/L	2023-11-27	Thornton Treatment Plant / 022
NMeFOSAA	< 0.006 µg/L	0.006 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFBA	0.0060 µg/L	0.005 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFBS	0.0042 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFDA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFDoA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFEESA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFHpA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFHpS	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFHxA	0.0056 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFHxS	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFMBA	< 0.003 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFMPA	< 0.004 µg/L	0.004 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFNA	< 0.004 µg/L	0.004 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFOA	< 0.004 µg/L	0.004 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFOS	< 0.004 µg/L	0.004 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFPeA	0.0055 µg/L	0.003 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFPeS	< 0.004 µg/L	0.004 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFTA	< 0.008 µg/L	0.008 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFTrDA	< 0.007 µg/L	0.007 µg/L	2023-11-27	Thornton Treatment Plant / 022
PFUnA	< 0.002 µg/L	0.002 µg/L	2023-11-27	Thornton Treatment Plant / 022
lithium	21.3 µg/L	9 µg/L	2023-11-27	Thornton Treatment Plant / 022

Download all EPA UCMR 5 records (CSV)

Lead and copper: 90th-percentile summaries

These describe a monitoring period across sampled locations, not the result at your home. How to read the 90th percentile

Eight most recent imported monitoring summaries
Substance	Published 90th percentile	Monitoring period	Source quarter
Lead (PB90)	0.0023 mg/L	2025-01-01 – 2025-12-31	2026Q3
Lead (PB90)	0.0014 mg/L	2024-01-01 – 2024-12-31	2026Q3
Lead (PB90)	0.0014 mg/L	2023-07-01 – 2023-12-31	2026Q3
Lead (PB90)	0.0017 mg/L	2023-01-01 – 2023-06-30	2026Q3
Lead (PB90)	0.0016 mg/L	2022-07-01 – 2022-12-31	2026Q3
Lead (PB90)	0.0012 mg/L	2022-01-01 – 2022-06-30	2026Q3
Lead (PB90)	0.0022 mg/L	2021-07-01 – 2021-12-31	2026Q3
Lead (PB90)	0.0018 mg/L	2021-01-01 – 2021-06-30	2026Q3

Published compliance history

8 imported records. Status is as recorded in the source; historical records are not current advisories. Missing records do not establish that no violations occurred.

Twenty most recent imported compliance records
Rule / record	Period	Recorded status	Health-based (EPA classification)	Source quarter
Interim and Long Term 1 Enhanced Surface Water Treatment Rule / Monitoring, Turbidity (Enhanced SWTR)	2023-11-01 – 2023-11-30	Resolved	No	2026Q3
Interim and Long Term 1 Enhanced Surface Water Treatment Rule / Monitoring, Turbidity (Enhanced SWTR)	2023-10-01 – 2023-10-31	Resolved	No	2026Q3
Interim and Long Term 1 Enhanced Surface Water Treatment Rule / Monitoring, Turbidity (Enhanced SWTR)	2023-09-01 – 2023-09-30	Resolved	No	2026Q3
Lead and Copper Rule / Follow-up Or Routine LCR Tap M/R	2023-07-01 – —	Resolved	No	2026Q3
Radionuclides and Revised Rad Rule / Monitoring, Regular	2022-04-01 – 2022-06-30	Resolved	No	2026Q3
Radionuclides and Revised Rad Rule / Monitoring, Regular	2022-04-01 – 2022-06-30	Resolved	No	2026Q3
Radionuclides and Revised Rad Rule / Monitoring, Regular	2022-04-01 – 2022-06-30	Resolved	No	2026Q3
Interim and Long Term 1 Enhanced Surface Water Treatment Rule / Monitoring, Turbidity (Enhanced SWTR)	2021-05-01 – 2021-05-31	Resolved	No	2026Q3

Source dates and refresh checks

A refresh check is not a sample date. Publication periods, sample dates and checks are shown separately.

EPA SDWIS lead/copper summaries and service areas — source period: — – —; last checked: 2026-10-17
EPA SDWIS contacts and compliance records — source period: — – —; last checked: 2026-10-17
EPA UCMR 5 sample results — source period: 2023-01-03 – 2026-06-17; last checked: 2026-10-17

Administrative contact (EPA filing)

Tedesco, Paul: 303-255-7775

An administrative filing contact may not be a customer-service line. Confirm current contact details with the provider.

Official state resources · How to read these records