Twin Hills Water System, AK
Lead detected, under the action levels
Latest 90th-percentile lead: 0.69 ppb (monitoring period 2021-2023). 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.
Twin Hills Water System at a glance
Twin Hills Water System serves about 87 people through 28 service connections, which makes it a very small system under EPA's size classes. It is owned by a Native American tribe and draws groundwater, in Dillingham Census Area County, Alaska. EPA system ID: AK2260032; phone on file: 907-525-4821. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
Against the period ending 2017 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Twin Hills Water System is 0.69 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 0.69 ppb |
| 2017 | 0 (not detected) |
Where this result ranks
Of the 394 Alaska systems with a lead result, the median latest reading is 1.6 ppb; 3 are over 15 ppb right now and 53 have gone over at some point. Twin Hills Water System's 0.69 ppb sits at the 29th percentile in Alaska and the 46th nationally (higher means more lead).
Other water systems in Dillingham Census Area County
10 other systems share Dillingham Census Area County; 5 of them have a higher latest lead result than Twin Hills Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Dillingham Water System | 2,419 | 0.4 ppb |
| Togiak Water System | 910 | 0.43 ppb |
| New Stuyahok Water System | 566 | 0.37 ppb |
| Bbahc - Kanakanak Hospital | 305 | 11 ppb |
| Manokotak Water System | 293 | 6.07 ppb |
| Manokotak Heights W/S | 215 | 0 (not detected) |
| Koliganek Water System | 170 | 2.7 ppb |
| Clarks Point Water System | 128 | 10.1 ppb |
| Salmon Roe | 31 | 5.4 ppb |
| Nina Nicholson Subdivision | 31 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Twin Hills, AK 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 Twin Hills 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.