Report identity and source
- Public water system
- City of Boulder
- PWSID
- CO0107152
- Report year
- 2026
- Official publisher/source
- City of Boulder 2026 Drinking Water Quality Report
- Source retrieved
- 2026-07-23
- Last reviewed
- 2026-07-23
Reviewed Report Rows
15 reviewed rows from the 2026 report
Measurements, ranges, units, limit fields, status cells, likely-source wording, and table names remain scoped to the named annual-report rows.
Disinfection
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Chlorine | Average: 0.89; Average: 0.89 | 0.31-1.36 | At least 120 samples per month in 2025 | ppm | MRDL: 4; MRDLG: 4 | TT Violation: No (row sample period) | 3 | Disinfection |
Inorganic Contaminants
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Barium | Average: 0.011; Average: 0.011 | 0.008-0.013 | 2025 | ppm | MCL: 2; MCLG: 2 | Violation: No (row sample period) | 3 | Inorganic Contaminants |
| Chromium | Average: 1.5; Average: 1.5 | 1.0-2.0 | 2025 | ppb | MCL: 100; MCLG: 100 | Violation: No (row sample period) | 3 | Inorganic Contaminants |
| Fluoride | Average: 0.54; Average: 0.54 | 0-0.84 | 2025 | ppm | MCL: 4; MCLG: 4 | Violation: No (row sample period) | 3 | Inorganic Contaminants |
| Sodium (secondary standard) | Average: 4.3; Average: 4.3 | 2.9-5.6 | 2025 | ppm | MCL: NE; MCLG: NE | Violation: No (row sample period) | 3 | Inorganic Contaminants |
| Nitrate | Average: 0.05; Average: 0.05 | 0-0.1 | 2025 | ppm | MCL: 10; MCLG: 10 | Violation: No (row sample period) | 3 | Inorganic Contaminants |
Turbidity Treatment Technique
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Turbidity - highest single measurement | Highest single measurement: 0.294; Average: 0.04 | 0.013-0.29 | Daily 2025 | NTU | TT Requirement: Not to exceed 1 NTU for any single measurement | Violation: No (row sample period) | 3 | Turbidity Treatment Technique |
| Turbidity - monthly treatment standard | Lowest monthly percentage of samples meeting TT standard: 100% | Monthly result: 100% | Monthly 2025 | NTU | TT Requirement: At least 95% of month's samples must be <= 0.3 NTU | Violation: No (row sample period) | 3 | Turbidity Treatment Technique |
Disinfection Treatment Technique
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Chlorine treatment technique | Lowest period percentage of samples meeting TT standard: 100% | Period result: 100% | At least 120 samples per month in 2025 | ppm | TT Requirement: At least 95% of month's samples must be at least 0.2 ppm | Violation: No (row sample period) | 4 | Disinfection Treatment Technique |
Lead and Copper Tap Monitoring
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Sites above action level | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|---|
| Copper | 90th Percentile: 0.17 | 0.02 to 2.19 | 1 | June 5, 2024-July 25, 2024 | ppm | AL: 1.3 | 90th Percentile AL: No (row sample period) | 4 | Lead and Copper Tap Monitoring |
| Lead | 90th Percentile: 2.0 | 0 to 11 | 0 | June 5, 2024-July 25, 2024 | ppb | AL: 15 | 90th Percentile AL: No (row sample period) | 4 | Lead and Copper Tap Monitoring |
Disinfection Byproducts Sampled in the Distribution System
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Haloacetic Acids | Highest LRAA: 33.71; Average: 30.4 | 17.01-38.73 | Quarterly 2025 | ppb | MCL: 60; MCLG: N/A | Violation: No (row sample period) | 4 | Disinfection Byproducts Sampled in the Distribution System |
| Total Trihalomethanes | Highest LRAA: 44.55; Average: 36.3 | 14.88-55.24 | Quarterly 2025 | ppb | MCL: 80; MCLG: N/A | Violation: No (row sample period) | 4 | Disinfection Byproducts Sampled in the Distribution System |
Total Organic Carbon Removal Ratio by Treatment Plant
reported report rows grouped under their printed table heading.
| Report row | Reported measurement | Range in report | Testing period in report | Unit | Limit or standard field | Status printed for this row | Source page | Source table |
|---|---|---|---|---|---|---|---|---|
| Total Organic Carbon Removal Ratio - Betasso WTP | Average removal ratio: 1.26; Average: 1.26 | 1.1-1.3 | 2025 | Not listed for this report row | Compliance Factor (Minimum TT Ratio): 1.0 | Violation: No (row sample period) | 4 | Disinfection Byproduct Precursor - Total Organic Carbon Removal Ratio |
| Total Organic Carbon Removal Ratio - 63rd WTP | Average removal ratio: 1.20; Average: 1.20 | 1.1-1.5 | 2025 | Not listed for this report row | Compliance Factor (Minimum TT Ratio): 1.0 | Violation: No (row sample period) | 4 | Disinfection Byproduct Precursor - Total Organic Carbon Removal Ratio |
Chlorine
- Likely source listed in report
- Water additive used to control microbes
- Source table
- Disinfection
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Barium
- Likely source listed in report
- Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits
- Source table
- Inorganic Contaminants
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Chromium
- Likely source listed in report
- Discharge from steel and pulp mills; erosion of natural deposits
- Source table
- Inorganic Contaminants
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Fluoride
- Likely source listed in report
- Erosion of natural deposits; water additive which promotes strong teeth
- Source table
- Inorganic Contaminants
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Sodium (secondary standard)
- Likely source listed in report
- Erosion of natural deposits
- Source table
- Inorganic Contaminants
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Nitrate
- Likely source listed in report
- Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits
- Source table
- Inorganic Contaminants
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Turbidity - highest single measurement
- Likely source listed in report
- Soil runoff
- Source table
- Turbidity Treatment Technique
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Turbidity - monthly treatment standard
- Likely source listed in report
- Soil runoff
- Source table
- Turbidity Treatment Technique
Preservation and source notes
- reported row transcribed from linked report page 3. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Chlorine treatment technique
- Likely source listed in report
- Water additive used to control microbes
- Source table
- Disinfection Treatment Technique
Preservation and source notes
- reported row transcribed from linked report page 4. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Copper
- Likely source listed in report
- Corrosion of household plumbing systems; erosion of natural deposits
- Source table
- Lead and Copper Tap Monitoring
Preservation and source notes
- The source prints one site over the action level and separately prints No for the 90th-percentile action-level determination. Both fields are preserved without inferring a violation or current condition.
Lead
- Likely source listed in report
- Corrosion of household plumbing systems; erosion of natural deposits
- Source table
- Lead and Copper Tap Monitoring
Preservation and source notes
- The source reports selected-tap monitoring from June 5 through July 25, 2024. This system-level 90th-percentile result is not a measurement for every tap or property.
Haloacetic Acids
- Likely source listed in report
- Byproduct of drinking water disinfection
- Source table
- Disinfection Byproducts Sampled in the Distribution System
Preservation and source notes
- reported row transcribed from linked report page 4. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Total Trihalomethanes
- Likely source listed in report
- Byproduct of drinking water disinfection
- Source table
- Disinfection Byproducts Sampled in the Distribution System
Preservation and source notes
- reported row transcribed from linked report page 4. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Total Organic Carbon Removal Ratio - Betasso WTP
- Likely source listed in report
- Naturally present in environment
- Source table
- Disinfection Byproduct Precursor - Total Organic Carbon Removal Ratio
Preservation and source notes
- reported row transcribed from linked report page 4. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Total Organic Carbon Removal Ratio - 63rd WTP
- Likely source listed in report
- Naturally present in environment
- Source table
- Disinfection Byproduct Precursor - Total Organic Carbon Removal Ratio
Preservation and source notes
- reported row transcribed from linked report page 4. Printed fields describe the row sample period and are not a present-day safety or compliance conclusion.
Report Context
Context attributed to the source report
These summaries are limited to the named annual report and do not assert live system, compliance, or advisory status.
Annual-report identity and scope
The official 2026 City of Boulder report directly prints PWSID CO0107152 and says it summarizes testing results from the 2025 calendar year.
Source-water context
The report names Barker Reservoir, North Boulder Creek, Carter Lake, and Boulder Reservoir and says the source reaching a home or business may vary seasonally.
Data-table scope
The table covers 2025 or the most recent required testing, may include data older than one year, and displays only detected contaminants sampled within the last five years.
General vulnerable-population notice
The report includes general EPA-required guidance for people who may be more vulnerable to contaminants and directs readers to health-care providers and the Safe Drinking Water Hotline. It is not a Boulder detection or advisory statement.
Printed 2025 violations statement
The report prints a 2025 violation count of zero. The statement is retained only as report-period context.
Service-line inventory context
The report describes continuing inventory work in 2025 and says no lead service lines were found during that investigation, while noting that some map classifications may use statistical analysis.
Lead and copper monitoring context
The report prints June 5 through July 25, 2024 for the lead and copper results and describes a reduced-monitoring schedule with the next sample period planned for 2027.
PFAS narrative scope
The report says six named PFAS were tested and not detected but prints no compound-specific values or sample period. No PFAS result row or future-compliance claim is created here.
Definitions
The report defines the regulatory terms and units used in its tables. They are reproduced as report-reading context, not as interpretation of any result.
Definitions printed in this report
- AVG
- Average: Typical value.
- AL
- Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.
- LRAA
- Locational Running Annual Average: The average of results for samples collected at a particular monitoring location during the most recent four calendar quarters.
- MCL
- Maximum Contaminant Level: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
- MCLG
- Maximum Contaminant Level Goal: The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
- MRDL
- Maximum Residual Disinfectant Level: The highest level of a disinfectant allowed in drinking water. There is evidence that addition of a disinfectant is necessary for control of microbial contaminants.
- MRDLG
- Maximum Residual Disinfectant Level Goal: The level of a drinking water disinfectant below which there is no known or expected risk to health.
- NE
- Not Established: A water quality regulatory threshold has not been set.
- NTU
- Nephelometric Turbidity Units: Units for turbidity, which is a measure of the clarity or cloudiness of water.
- ppb
- Parts Per Billion: Same as micrograms per liter (µg/l).
- ppm
- Parts Per Million: Same as milligrams per liter (mg/l).
- RAA
- Running Annual Average: An average of monitoring results for the previous 12 calendar months or the previous four quarters.
- TT
- Treatment Technique: A required process intended to reduce the level of contaminants in drinking water.
How to read a water quality report
A plain-English walkthrough of Consumer Confidence Reports, including report years, detected contaminants, legal limits, violations, and source notes.
View How to read a water quality reportReport Disclosures
Source-period disclosures kept separate from live status
These items preserve report wording and scope. They do not create violation records, advisory records, or a current-status conclusion.
Annual report is not current status
The 2026 document summarizes 2025 and other most-recent required monitoring. Its result cells and narrative do not establish present-day compliance, advisory status, safety, or conditions at a household tap.
Current status is not asserted. Check official current sources for notices or instructions.
2025 no-violations statement
The report prints a 2025 violation count of zero. This is attributed only to the printed report period and is not a claim about current compliance, current notices, safety, or household-tap conditions.
Current status is not asserted. Check official current sources for notices or instructions.
Annual report is not a live notice page
The annual report provides City contact and information paths but does not establish whether a current advisory exists. Check the official City of Boulder Drinking Water Quality and CDPHE sources linked from the system profile for current information.
Current status is not asserted. Check official current sources for notices or instructions.
Source water varies and is not address-level proof
The report names four source waters and says the source reaching a home or business may vary by season. This does not assign a source to a specific address, and potential sources identified by source-water planning do not establish contaminant occurrence.
Current status is not asserted. Check official current sources for notices or instructions.
Inventory is not property-level proof
The report says the City continued service-line inventory work in 2025 and found no lead service lines during that investigation. It also says some map classifications may use statistical analysis. These statements do not establish the material at a specific property or prove that every line was directly inspected.
Current status is not asserted. Check official current sources for notices or instructions.
System sampling is not a household-tap result
The 2024 lead and copper results summarize selected-tap monitoring. They do not describe every service line, plumbing configuration, property, or household tap.
Current status is not asserted. Check official current sources for notices or instructions.
PFAS narrative has no result table
The report says six named PFAS were tested and not detected, then discusses changing regulation and anticipated future compliance. It prints no compound-specific value or sample period, so this page does not create PFAS result rows or a current regulatory or compliance determination.
Current status is not asserted. Check official current sources for notices or instructions.
Evidence
Official report and system source paths
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Report identity and field provenance
- Annual report document: City of Boulder 2026 Drinking Water Quality Report Six-page PDF; SHA-256 c6229b168b013933b0080082ccb13a6ce6805b43afd64d0fe9b4f06b9ca4f97b.
- PWSID CO0107152: City of Boulder 2026 Drinking Water Quality Report Page 1 directly prints Public Water System ID: CO0107152.
- Report year and printed data periods: City of Boulder 2026 Drinking Water Quality Report The 2026 report summarizes 2025; individual rows retain their printed 2024 or 2025 periods.
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Methodology
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