Water Quality
Safe Drinking Water
The Safe Drinking Water Act (SDWA) protects the quality of drinking water across the U.S. It requires all public water systems, including Big Sky’s, to regularly test water sources for more than 90 primary contaminants—including inorganics, organics, radionuclides, and microorganisms.
- Primary standards are enforceable and based on health protection.
- Secondary standards are non-enforceable guidelines based on aesthetics such as taste, odor, and color, as well as properties like hardness and corrosivity.
A full list of test results for all District wells is available at our office, and summarized each year in our Consumer Confidence Report (CCR).
Consumer Confidence Report (CCR)
Every public water supplier must provide a CCR to customers by July 1 each year, covering the previous calendar year. The CCR includes:
- Water source and quality
- Compliance and treatment information
- Any exceedances of primary standards
- Health and educational information
You can view the most recent CCR and reports from the last five years here or hard copies are also available at the District office.
PFAS Testing
In addition to required SDWA monitoring, WSD 363 has tested its wells for Per- and Polyfluoroalkyl Substances (PFAS). These are emerging contaminants of national concern because they persist in the environment and may affect human health. All of Big Sky’s PFAS test results are well below EPA’s proposed regulatory limits. This means our water continues to meet all state and federal drinking water standards. For details, see the latest CCR or contact our office to review full PFAS sampling results.
Water Hardness
Water hardness is a secondary standard but is often of interest to our customers:
- Meadow Village wells: ~260 mg/L (very hard)
- Mountain Village wells: ~63 mg/L (moderately hard)
Additional Information
Below are some of the most requested water quality parameters. For a complete list, please see the current CCR. If you have questions, please contact our office and ask to speak with one of our water operators.
Consumer Confidence Reports
Also known as an Annual Water Quality Report or Drinking Water Quality Report, the CCR provides important information about your local drinking water quality. The U.S. Environmental Protection Agency (EPA) requires every community water supplier to deliver this report to customers each year by July 1, under the Consumer Confidence Report Rule.
Our District publishes a CCR each year that summarizes the quality of drinking water for our two permitted public water systems: Meadow Village and Mountain Village. Each report includes a summary table of testing results and other important details about your water.
Click the links below to view the CCRs for the past six years. Hard copies are also available at our office upon request.
For more information about Consumer Confidence Reports, please visit the EPA website.
General Water Quality Information
Mountain System
| Parameter | Amount Detected |
|---|---|
| Calcium | 21.4 mg/l |
| Magnesium | 5.2 mg/l |
| Potassium | 0.9 mg/l |
| Sodium | 15.4 mg/l |
| Hardness, Total as CaCO3 | 73.2 mg/l |
| Chloride | 11.6 mg/l |
| Sulfate | 7.1 mg/l |
| Alkalinity as CaCO3 | 83.1 mg/l |
| Specific Conductance @ 25°C | 141 umhos/cm |
| Solids, Total Dissolved – Calculated | 152 mg/l |
| pH | 7.8 s.u. |
| Nitrogen, Nitrate plus Nitrite | 0.4 mg/l |
| Iron, Total | 0.02 mg/l |
| Fluoride | <0.1 mg/l |
Meadow System
| Parameter | Amount Detected |
|---|---|
| Calcium | 87.8 mg/l |
| Magnesium | 18.2 mg/l |
| Potassium | 2.5 mg/l |
| Sodium | 19.0 mg/l |
| Hardness, Total as CaCO3 | 270 mg/l |
| Chloride | 38.7 mg/l |
| Sulfate | 12.7 mg/l |
| Alkalinity as CaCO3 | 212 mg/l |
| Specific Conductance @ 25°C | 549 umhos/cm |
| Solids, Total Dissolved – Calculated | 372 mg/l |
| pH | 7.6 s.u. |
| Nitrogen, Nitrate plus Nitrite | 3.7 mg/l |
| Iron, Total | 0.02 mg/l |
| Fluoride | <0.1 mg/l |
*Floride is considered an inorganic chemical and is not sampled for under domestic use parameters.
PFAS Monitoring Results – UCMR 5
Public Water System ID: MT0002385
System Name: Big Sky County Water & Sewer District 363
| Meadow and Mountain Entry Points | |
|---|---|
| Analyte Name | Reported Value |
| PFBS | <0.003 µg/l |
| PGHpA | <0.003 µg/l |
| PFHxS | <0.003 µg/l |
| PFNA | <0.004 µg/l |
| PFOS | <0.004 µg/l |
| PFOA | <0.004 µg/l |
| PFDA | <0.003 µg/l |
| PFDoA | <0.003 µg/l |
| PFHxA | <0.003 µg/l |
| PFUnA | <0.002 µg/l |
| 11Cl-PF3OUdS | <0.005 µg/l |
| 9Cl-PF3ONS | <0.002 µg/l |
| ADONA | <0.003 µg/l |
| HFPO-DA | <0.005 µg/l |
| PFBA | <0.005 µg/l |
| 6:2 FTS | <0.005 µg/l |
| 4:2 FTS | <0.003 µg/l |
| 8:2 FTS | <0.005 µg/l |
| PFMPA | <0.004 µg/l |
| PFPeA | <0.003 µg/l |
| PFMBA | <0.003 µg/l |
| PFEESA | <0.003 µg/l |
| NFDHA | <0.02 µg/l |
| PFPeS | <0.004 µg/l |
| PFHpS | <0.003 µg/l |
Sampling (March 2025)
Sampling Date: March 18, 2025
Method Used: EPA 533
| Analyte Name | Reported Value |
|---|---|
| PFBS | <0.003 µg/l |
| PGHpA | <0.003 µg/l |
| PFHxS | <0.003 µg/l |
| PFNA | <0.004 µg/l |
| PFOS | <0.004 µg/l |
| PFOA | <0.004 µg/l |
| PFDA | <0.003 µg/l |
| PFDoA | <0.003 µg/l |
| PFHxA | <0.003 µg/l |
| PFUnA | <0.002 µg/l |
| 11Cl-PF3OUdS | <0.005 µg/l |
| 9Cl-PF3ONS | <0.002 µg/l |
| ADONA | <0.003 µg/l |
| HFPO-DA | <0.005 µg/l |
| PFBA | <0.005 µg/l |
| 6:2 FTS | <0.005 µg/l |
| 4:2 FTS | <0.003 µg/l |
| 8:2 FTS | <0.005 µg/l |
| PFMPA | <0.004 µg/l |
| PFPeA | <0.003 µg/l |
| PFMBA | <0.003 µg/l |
| PFEESA | <0.003 µg/l |
| NFDHA | <0.02 µg/l |
| PFPeS | <0.004 µg/l |
| PFHpS | <0.003 µg/l |