Mountain Ridge, WA
Lead detected, under the action levels
Latest 90th-percentile lead: 3.5 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.
About Mountain Ridge
Mountain Ridge serves about 28 people through 21 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Kittitas County, Washington. EPA system ID: WA53AB326. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is down 4.5 ppb from 8 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Mountain Ridge is 8 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 3.5 ppb |
| 2024 | 8 ppb |
Where this result ranks
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. Mountain Ridge's 3.5 ppb sits at the 84th percentile in Washington and the 85th nationally (higher means more lead).
Neighbouring systems
36 other systems share Kittitas County; 2 of them have a higher latest lead result than Mountain Ridge. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Ellensburg Water Dept | 20,900 | 1.5 ppb |
| Suncadia Resort | 2,640 | 13 ppb |
| Kittitas City Of | 2,247 | 1 ppb |
| Cle Elum Water Department | 2,213 | 0 (not detected) |
| Roslyn City Of | 2,099 | 0 (not detected) |
| Kittitas County Water District #5 | 700 | 0 (not detected) |
| South Cle Elum Water Dept | 541 | 0 (not detected) |
| Kittitas County Water District #4 | 510 | 0 (not detected) |
| Kittitas County Water District #7 | 463 | 0 (not detected) |
| Vantage Water System | 405 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Roslyn, WA 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 Mountain Ridge 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. The action level is dropping - the 10 ppb rule from 2027.