Idaho City Water Dept, ID
Lead detected, under the action levels
Latest 90th-percentile lead: 2 ppb (monitoring period 2025-2025). 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.
Who runs the water here
Idaho City Water Dept serves about 531 people through 283 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws surface water, in Boise County, Idaho. EPA system ID: ID4080025; phone on file: 208-392-4584. They can tell you what your service line is made of and whether they pay to replace it.
Idaho City Water Dept's lead record
That is up 2 ppb from 0 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Idaho City Water Dept is 4 ppb across 8 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2 ppb |
| 2024 | 0 (not detected) |
| 2024 | 3 ppb |
| 2023 | 2 ppb |
| 2023 | 4 ppb |
| 2022 | 1 ppb |
| 2020 | 3 ppb |
| 2017 | 4 ppb |
How Idaho City Water Dept 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. Idaho City Water Dept's 2 ppb sits at the 70th percentile in Idaho and the 71st nationally (higher means more lead).
Other water systems in Boise County
19 other systems share Boise County; 8 of them have a higher latest lead result than Idaho City Water Dept. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Horseshoe Bend Water Supply | 750 | 2 ppb |
| Wilderness Ranch Owners Association Inc | 525 | 4 ppb |
| Terrace Lakes Water Company | 475 | 4 ppb |
| Mountain View Water And Road Assn | 305 | 2 ppb |
| Castle Mountain Creeks Owners Assn | 250 | 1 ppb |
| Duquette Pines Homeowners Association | 163 | 1 ppb |
| Scriver Woods Homeowners Assn | 160 | 0 (not detected) |
| Mores Creek Rim Ranch Water Dist | 140 | 3 ppb |
| Rivers Point Property Owners Assn | 140 | 3 ppb |
| Valley Hi Estates | 140 | 8 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Idaho City, 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 Idaho City Water Dept 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. What a 90th-percentile result does and does not tell you: how to read a lead result. Size matters more than most people expect: small vs large water systems.