Greatrock North Wsd, CO
Lead detected, under the action levels
Latest 90th-percentile lead: 2 ppb (monitoring period 2023-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
About Greatrock North Wsd
Greatrock North Wsd serves about 1,250 people through 500 service connections, which makes it a small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Adams County, Colorado. EPA system ID: CO0101063; phone on file: 303-439-6029. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
Against the period ending 2021 (1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Greatrock North Wsd is 2 ppb across 6 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2 ppb |
| 2021 | 1 ppb |
| 2020 | 0 (not detected) |
| 2019 | 1 ppb |
| 2018 | 0 (not detected) |
| 2017 | 0 (not detected) |
Against other Colorado systems
Of the 1,025 Colorado systems with a lead result, the median latest reading is 1 ppb; 2 are over 15 ppb right now and 71 have gone over at some point. Greatrock North Wsd's 2 ppb sits at the 73rd percentile in Colorado and the 72nd nationally (higher means more lead).
Other water systems in Adams County
62 other systems share Adams County; 11 of them have a higher latest lead result than Greatrock North Wsd. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Thornton City Of | 226,465 | 2.3 ppb |
| Westminster City Of | 202,078 | 1.3 ppb |
| South Adams County Wsd | 75,559 | 0 (not detected) |
| Brighton City Of | 56,304 | 2 ppb |
| Northglenn City Of | 48,927 | 1.7 ppb |
| Crestview Wsd | 23,756 | - |
| North Washington Street Wsd | 14,500 | - |
| Federal Heights City Of | 11,678 | 1.7 ppb |
| Todd Creek Village Md | 7,363 | 0.8 ppb |
| Bennett Town Of | 4,400 | 1 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Broomfield, CO may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Greatrock North Wsd whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. Systems that went over once often dip back under; here is what that means.