Thompson Heights Water System, TX
Lead detected, under the action levels
Latest 90th-percentile lead: 2.09 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.
Who runs the water here
Thompson Heights Water System serves about 414 people through 138 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws surface water, in Grayson County, Texas. EPA system ID: TX0910085; phone on file: 903-463-2300. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
Against the period ending 2022 (3 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Thompson Heights Water System is 3 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2.09 ppb |
| 2022 | 3 ppb |
Against other Texas systems
Of the 4,447 Texas systems with a lead result, the median latest reading is 0.28 ppb; 15 are over 15 ppb right now and 202 have gone over at some point. Thompson Heights Water System's 2.09 ppb sits at the 84th percentile in Texas and the 74th nationally (higher means more lead).
Nearby utilities
39 other systems share Grayson County; 4 of them have a higher latest lead result than Thompson Heights Water System. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| City Of Sherman | 43,645 | 0 (not detected) |
| City Of Denison | 27,500 | 1.82 ppb |
| City Of Van Alstyne | 10,644 | 0.81 ppb |
| Two Way Sud | 6,804 | 0 (not detected) |
| South Grayson Sud | 6,750 | 7.49 ppb |
| City Of Howe | 4,548 | 0 (not detected) |
| Kentuckytown Wsc | 4,455 | 2.08 ppb |
| Tanglewood On Texoma | 4,341 | 0 (not detected) |
| Luella Sud | 4,200 | 0 (not detected) |
| City Of Whitesboro | 4,192 | 0 (not detected) |
Next steps for Denison, TX
Test your own tap with a certified lab first-draw sample; Denison, TX 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 Thompson Heights 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. 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.