What was found in Castle Rock's water
The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Fluoride | 1580 µg/L 40% of the EPA limit 4000 µg/L | 6/6 | SYR4 |
| Nitrate | 1300 µg/L 13% of the EPA limit 10000 µg/L | 5/6 | SYR4 |
| Barium | 520 µg/L 26% of the EPA limit 2000 µg/L | 6/6 | SYR4 |
| Nitrate-Nitrite | 400 µg/L 4% of the EPA limit 10000 µg/L | 3/6 | SYR4 |
| TTHM | 67.49 µg/L 84% of the EPA limit 80 µg/L | 5/6 | SYR4 |
| Lithium | 30.9 µg/L No EPA limit set | 2/6 | UCMR-5 |
| Xylenes, Total | 27.5 µg/L 0.3% of the EPA limit 10000 µg/L | 1/6 | SYR4 |
| Gross Alpha, Excl. Radon And U | 14.794 pCi/L 99% of the EPA limit 15 pCi/L | 6/6 | SYR4 |
| Dibromochloromethane | 14.1 µg/L No EPA limit set | 5/6 | SYR4 |
| Combined Radium (-226 And -228) | 9.8 pCi/L 196% of the EPA limit, in the worst sample — 5 pCi/L | 6/6 | SYR4 |
| Bromodichloromethane | 9.3 µg/L No EPA limit set | 5/6 | SYR4 |
| Total Haloacetic Acids (HAA5) | 9.3 µg/L 16% of the EPA limit 60 µg/L | 4/6 | SYR4 |
| Bromoform | 7.49 µg/L No EPA limit set | 2/6 | SYR4 |
| Gross Beta Particle Activity | 7 pCi/L No EPA limit set | 3/6 | SYR4 |
| Chloroform | 5.3 µg/L No EPA limit set | 5/6 | SYR4 |
| Selenium | 5 µg/L 10% of the EPA limit 50 µg/L | 5/6 | SYR4 |
| Dibromoacetic Acid | 4.6 µg/L No EPA limit set | 2/6 | SYR4 |
| Dichloroacetic Acid | 4.5 µg/L No EPA limit set | 2/6 | SYR4 |
| Arsenic | 3 µg/L 30% of the EPA limit 10 µg/L | 2/6 | SYR4 |
| Chromium | 3 µg/L 3% of the EPA limit 100 µg/L | 3/6 | SYR4 |
| Combined Uranium | 3 µg/L 10% of the EPA limit 30 µg/L | 3/6 | SYR4 |
| Ethylbenzene | 2.3 µg/L 0.3% of the EPA limit 700 µg/L | 1/6 | SYR4 |
| Monobromoacetic Acid | 2.2 µg/L No EPA limit set | 1/6 | SYR4 |
| Thallium, Total | 2 µg/L 100% of the EPA limit 2 µg/L | 1/6 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 1.9 µg/L 32% of the EPA limit 6 µg/L | 2/6 | SYR4 |
| Trichloroacetic Acid | 1.3 µg/L No EPA limit set | 1/6 | SYR4 |
| Monochloroacetic Acid | 1.29 µg/L No EPA limit set | 1/6 | SYR4 |
| Picloram | 0.1000 µg/L 0% of the EPA limit 500 µg/L | 1/6 | SYR4 |
| Heptachlor | 0.0400 µg/L 10% of the EPA limit 0.4000 µg/L | 1/6 | SYR4 |
| Pfba | 0.0051 µg/L No EPA limit set | 1/6 | UCMR-5 |
| Pfpea | 0.0047 µg/L No EPA limit set | 1/6 | UCMR-5 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L | 6/6 | LCR |
Water suppliers serving Castle Rock
| Supplier | Population served |
|---|---|
| CASTLE ROCK TOWN OF | 110,298 |
| CASTLE PINES VILLAGE MD | 5,656 |
| CONSOLIDATED BELL MTN RANCH MD | 1,162 |
| BEVERLY HILLS MUTUAL WC | 325 |
| SILVER HEIGHTS WSD | 301 |
| LOUVIERS WSD | 238 |
Frequently asked questions about Castle Rock tap water
Is Castle Rock tap water safe to drink?
EPA testing detected 32 contaminants in the water serving Castle Rock. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Castle Rock?
6 public water suppliers report drinking-water monitoring for Castle Rock, Colorado to the EPA. Each is listed above with its population served.
What contaminants are in Castle Rock's water?
The contaminants EPA monitoring detected in Castle Rock include Fluoride, Nitrate, Barium, Nitrate-Nitrite, TTHM. The full list, with the highest level found and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.