2025 Table of Detected Regulated Contaminants For Southern Black Hills Water (EPA ID 2309)
Terms and abbreviations used in this table:
- Maximum Contaminant Level Goal(MCLG):
- 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.
- Maximum Contaminant Level(MCL):
- 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.
- Action Level(AL):
- the concentration of a contaminant which, when exceeded, triggers treatment or other requirements which a water system must follow. For Lead and Copper, 90% of the samples must be below the AL.
- Treatment Technique(TT):
- A required process intended to reduce the level of a contaminant in drinking water. For turbidity, 95% of samples must be less than 0.3 NTU
- Running Annual Average(RAA):
- Compliance is calculated using the running annual average of samples from designated monitoring locations.
Units:
| MFL: million fibers per liter | pCi/l: picocuries per liter(a measure of radioactivity) | ppt: parts per trillion, or nanograms per liter |
| mrem/year: millirems per year(a measure of radiation absorbed by the body) | ppm: parts per million, or milligrams per liter(mg/l) | ppq: parts per quadrillion, or picograms per liter |
| NTU: Nephelometric Turbidity Units | ppb: parts per billion, or micrograms per liter(ug/l) | pspm: positive samples per month |
| Substance | 90% Level | Test Sites > Action Level | Date Tested | Highest Level Allowed (AL) | Ideal Goal | Units | Major Source of Contaminant |
|---|---|---|---|---|---|---|---|
| Copper | 0.1 | 0 | 09/10/25 | AL=1.3 | 0 | ppm | Corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives. |
| Lead | 2 | 0 | 09/10/25 | AL=15 | 0 | ppb | Corrosion of household plumbing systems; erosion of natural deposits. |
| Substance | Highest Level Detected | Range | Date Tested | Highest Level Allowed (MCL) | Ideal Goal (MCLG) | Units | Major Source of Contaminant |
|---|---|---|---|---|---|---|---|
| Alpha emitters | 1 | ND - 1 | 11/01/22 | 15 | 0 | pCi/l | Erosion of natural deposits. |
| Arsenic | 9.00 | 9.00 - 9.00 | 08/26/25 | 10 | 0 | ppb | Erosion of natural deposits; runoff from orchards; runoff from glass and electronics production wastes. |
| Barium | 0.1120 | 0.1120 - 0.1120 | 11/01/22 | 2 | 2 | ppm | Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits. |
| Combined Radium | 2 | ND - 2 | 11/01/22 | 5 | 0 | pCi/l | Erosion of natural deposits. |
| Fluoride | 0.30 | 0.30 - 0.30 | 11/01/22 | 4 | <4 | ppm | Erosion of natural deposits; water additive which promotes strong teeth; discharge from fertilizer and aluminum factories. |
| Nitrate (as Nitrogen) | 0.494 | 08/26/25 | 10 | 10 | ppm | Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits. | |
| Total trihalomethanes (RAA) | 11.8 | 09/15/25 | 80 | 0 | ppb | By-product of drinking water chlorination. Results are reported as a running annual average of test results. |
Please direct questions regarding this information to Mr Don Peterson with the Southern Black Hills Water public water system at (605)745-4669.
