Sierra Water Corp, ID
Lead detected, under the action levels
Latest 90th-percentile lead: 2 ppb (monitoring period 2022-2024). 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.
Sierra Water Corp at a glance
Sierra Water Corp serves about 70 people through 22 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Ada County, Idaho. EPA system ID: ID4010133; phone on file: 208-789-4574. 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 up 2 ppb from 0 ppb in the period ending 2022. The highest 90th-percentile result EPA holds for Sierra Water Corp is 5 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 2 ppb |
| 2022 | 0 (not detected) |
| 2019 | 5 ppb |
| 2016 | 0 (not detected) |
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. Sierra Water Corp's 2 ppb sits at the 62nd percentile in Idaho and the 70th nationally (higher means more lead).
Other water systems in Ada County
52 other systems share Ada County; 12 of them have a higher latest lead result than Sierra Water Corp. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Veolia Water Idaho | 264,978 | 2 ppb |
| Meridian Water Dept | 152,070 | 3.9 ppb |
| Kuna City Of | 32,038 | 0 (not detected) |
| Star Sewer And Water Dist Water System | 14,000 | 1 ppb |
| Garden City Water And Sewer System | 12,500 | 1 ppb |
| Capitol Water Corp | 9,000 | 3 ppb |
| Eagle, City Of (Western Zone) | 6,108 | 1 ppb |
| Eagle, City Of (Eastern Zone) | 3,702 | 4 ppb |
| Idoc Sbx Complex | 3,309 | 0 (not detected) |
| Idoc Idaho State Correctional Center | 2,204 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Eagle, 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 Sierra Water Corp 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. The lead result guide covers how utilities pick the homes they sample. Systems that went over once often dip back under; here is what that means.