Magnolia-Trewhill, MO
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Magnolia-Trewhill serves about 207 people through 69 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Lafayette Parish County, Missouri. EPA system ID: LA1055148; phone on file: 314-464-4790. They can tell you what your service line is made of and whether they pay to replace it.
Magnolia-Trewhill's lead record
Against the period ending 2022 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Magnolia-Trewhill is 3 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2022 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2016 | 3 ppb |
How Magnolia-Trewhill compares
Of the 1,674 Missouri systems with a lead result, the median latest reading is 1.04 ppb; 2 are over 15 ppb right now and 74 have gone over at some point. Magnolia-Trewhill's reported as 0 (not detected) sits at the 15th percentile in Missouri and the 15th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
22 other systems share Lafayette Parish County; 6 of them have a higher latest lead result than Magnolia-Trewhill. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Magnolia-Le Triomphe Subdivision | 1,278 | 0.79 ppb |
| Magnolia-Jackson Square | 825 | 0 (not detected) |
| Magnolia-Windy Meadows | 549 | 1 ppb |
| Magnolia-Garden Heights Subdivision Ws | 483 | 0 (not detected) |
| Magnolia-Markridge Park Subdivision | 468 | 0 (not detected) |
| Magnolia-Beau Parterre | 462 | 0 (not detected) |
| Magnolia-Shenandoah Estates | 396 | 0.41 ppb |
| Magnolia-Ossun Heights | 393 | 0 (not detected) |
| Magnolia-Carencro Village | 315 | 0 (not detected) |
| Magnolia-Coach House Manor | 315 | 3 ppb |
Next steps for St. Louis, MO
Look up your address in Magnolia-Trewhill's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Magnolia-Trewhill 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. The lead result guide covers how utilities pick the homes they sample. A zero today does not rule out a jump later - the rules are tightening in 2027.