Mountain City Water Dept, TN
Lead detected, under the action levels
Latest 90th-percentile lead: 0.9 ppb (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. 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.
Mountain City Water Dept at a glance
Mountain City Water Dept serves about 9,304 people through 4,117 service connections, which makes it a medium-sized system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Johnson County, Tennessee. EPA system ID: TN0000479. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
Against the period ending 2022 (0.9 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Mountain City Water Dept is 1.04 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0.9 ppb |
| 2022 | 0.9 ppb |
| 2019 | 0.56 ppb |
| 2016 | 1.04 ppb |
How Mountain City Water Dept compares
Of the 453 Tennessee systems with a lead result, the median latest reading is 1 ppb; 0 are over 15 ppb right now and 10 have gone over at some point. Mountain City Water Dept's 0.9 ppb sits at the 23rd percentile in Tennessee and the 49th nationally (higher means more lead).
Other water systems in Johnson County
2 other systems share Johnson County; 2 of them have a higher latest lead result than Mountain City Water Dept. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Carderview Utility District | 1,049 | 1 ppb |
| Brownlow Utility District | 683 | 1 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Mountain City, TN 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 City Water Dept 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. Size matters more than most people expect: small vs large water systems.