Tonasket Water System, WA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Tonasket Water System serves about 2,398 people through 602 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 Okanogan County, Washington. EPA system ID: WA5388700. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is down 1.6 ppb from 1.6 ppb in the period ending 2022. The highest 90th-percentile result EPA holds for Tonasket Water System is 3.9 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2022 | 1.6 ppb |
| 2019 | 1.1 ppb |
| 2016 | 3.9 ppb |
How Tonasket Water System compares
Of the 2,218 Washington systems with a lead result, the median latest reading is 1 ppb; 18 are over 15 ppb right now and 62 have gone over at some point. Tonasket Water System's reported as 0 (not detected) sits at the 32nd percentile in Washington and the 32nd nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
42 other systems share Okanogan County; 23 of them have a higher latest lead result than Tonasket Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Omak City Of | 4,940 | 3 ppb |
| Brewster City Of | 3,843 | 1.7 ppb |
| Okanogan Water Department City Of | 3,817 | 1.4 ppb |
| Oroville City Of | 3,256 | 3.2 ppb |
| Coulee Dam Water Dept | 1,454 | 1.7 ppb |
| Winthrop Town Of | 1,350 | 1 ppb |
| Twisp Town Of | 1,173 | 1.1 ppb |
| Monse-Riggan Camp | 1,165 | 0 (not detected) |
| Pateros Water Department | 1,149 | 2.8 ppb |
| Jaw Farms Inc | 636 | 0 (not detected) |
Your move
Look up your address in Tonasket Water System's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Tonasket Water System 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. Small systems behave differently: why small systems go over more often.