Winchester Water Dept, ID
Lead detected, under the action levels
Latest 90th-percentile lead: 1 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
Winchester Water Dept serves about 400 people through 217 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Lewis County, Idaho. EPA system ID: ID2310007; phone on file: 208-924-5358. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Winchester Water Dept's lead record
That is down 3 ppb from 4 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Winchester Water Dept is 4 ppb across 14 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 1 ppb |
| 2024 | 4 ppb |
| 2023 | 0 (not detected) |
| 2022 | 0 (not detected) |
| 2021 | 1 ppb |
| 2021 | 1 ppb |
| 2020 | 0 (not detected) |
| 2020 | 2 ppb |
| 2019 | 1 ppb |
| 2019 | 0 (not detected) |
| 2018 | 1 ppb |
| 2017 | 0 (not detected) |
| 2016 | 1 ppb |
| 2016 | 3 ppb |
Against other Idaho systems
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. Winchester Water Dept's 1 ppb sits at the 52nd percentile in Idaho and the 53rd nationally (higher means more lead).
Nearby utilities
5 other systems share Lewis County; 2 of them have a higher latest lead result than Winchester Water Dept. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Kamiah City Of | 1,495 | 2 ppb |
| Craigmont City Of | 501 | 0 (not detected) |
| Nezperce Water Dept | 460 | 2 ppb |
| Reubens City Of | 70 | 0 (not detected) |
| Lawyers Creek Water Dist | 50 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Winchester, 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 Winchester 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.