Ynp-Old Faithful, WY
Exceeded the action level in the past
Latest 90th-percentile lead: 2 ppb (monitoring period 2026-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest result is under the action level, but this system has gone over 15 ppb before. Lead comes from pipes, not the source water, so a home with a lead service line can still be exposed. Test your own tap.
Ynp-Old Faithful at a glance
Ynp-Old Faithful serves about 7,745 people through 160 service connections, which makes it a medium-sized system under EPA's size classes. It is federally owned and draws surface water, in Teton County, Wyoming. EPA system ID: WY5680085; phone on file: 307-344-9051. They can tell you what your service line is made of and whether they pay to replace it.
Ynp-Old Faithful's lead record
That is down 4 ppb from 6 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Ynp-Old Faithful is 125 ppb across 8 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 2 ppb |
| 2025 | 6 ppb |
| 2024 | 4 ppb |
| 2024 | 4 ppb |
| 2023 | 125 ppb over 15 |
| 2020 | 3 ppb |
| 2020 | 1 ppb |
| 2017 | 4 ppb |
Against other Wyoming systems
Of the 311 Wyoming systems with a lead result, the median latest reading is 1 ppb; 0 are over 15 ppb right now and 16 have gone over at some point. Ynp-Old Faithful's 2 ppb sits at the 75th percentile in Wyoming and the 73rd nationally (higher means more lead).
Nearby utilities
37 other systems share Teton County; 10 of them have a higher latest lead result than Ynp-Old Faithful. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Jackson, Town Of | 24,760 | 1 ppb |
| Ynp - Lake Village | 5,925 | 4 ppb |
| Gtnp-Colter Bay Village | 4,514 | 1 ppb |
| Gtnp-Jackson Lake Lodge | 1,830 | 2 ppb |
| Rafter J Subdivision Hoa | 1,500 | 3 ppb |
| Aspens Pines W&S District | 1,400 | 2 ppb |
| Teton Village Water & Sewer District | 906 | 2 ppb |
| Melody Ranch Improvement & Service Dist. | 900 | 5 ppb |
| Spring Creek Improvement District | 400 | 3 ppb |
| Snake River Sporting Club | 332 | 5 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Yellowstone, WY 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 Ynp-Old Faithful 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. More in what a past exceedance means today.