Greenhorn Subd, ID
Lead detected, under the action levels
Latest 90th-percentile lead: 1.97 ppb (monitoring period 2026-2026). 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.
Who runs the water here
Greenhorn Subd serves about 75 people through 29 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Blaine County, Idaho. EPA system ID: ID5070020; phone on file: 208-720-5893. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
That is down 2.03 ppb from 4 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Greenhorn Subd is 8 ppb across 11 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 1.97 ppb |
| 2025 | 4 ppb |
| 2025 | 2 ppb |
| 2024 | 8 ppb |
| 2024 | 6 ppb |
| 2023 | 4 ppb |
| 2023 | 8 ppb |
| 2022 | 3 ppb |
| 2022 | 2 ppb |
| 2019 | 4 ppb |
| 2016 | 6 ppb |
How Greenhorn Subd compares
Of the 763 Idaho systems with a lead result, the median latest reading is 1 ppb; 3 are over 15 ppb right now and 46 have gone over at some point. Greenhorn Subd's 1.97 ppb sits at the 58th percentile in Idaho and the 69th nationally (higher means more lead).
Neighbouring systems
19 other systems share Blaine County; 11 of them have a higher latest lead result than Greenhorn Subd. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Hailey Water And Sewer | 8,000 | 2 ppb |
| Ketchum City Of | 3,555 | 9 ppb |
| Sun Valley Water And Sewer Dist | 3,400 | 4 ppb |
| Bellevue City Of | 2,747 | 0 (not detected) |
| Carey City Of | 993 | 4 ppb |
| Mid Valley Water Company Llc | 450 | 0 (not detected) |
| Hulen Meadows Water Company | 390 | 5 ppb |
| Cold Springs Subd | 300 | 0 (not detected) |
| Heatherlands Subd | 200 | 1 ppb |
| Starweather Estates | 150 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Ketchum, ID 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 Greenhorn Subd 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. Size matters more than most people expect: small vs large water systems.