Magnolia-Guste Island, MO
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2022-2024). 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.
Magnolia-Guste Island at a glance
Magnolia-Guste Island serves about 2,847 people through 949 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in St. Tammany Parish County, Missouri. EPA system ID: LA1103189; phone on file: 314-380-5545. 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 2021 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Magnolia-Guste Island is 0 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2018 | 0 (not detected) |
| 2018 | 0 (not detected) |
Against other Missouri systems
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-Guste Island's reported as 0 (not detected) sits at the 35th percentile in Missouri and the 32nd nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
25 other systems share St. Tammany Parish County; 10 of them have a higher latest lead result than Magnolia-Guste Island. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Magnolia-Eden Isles | 10,155 | 1 ppb |
| Magnolia-Greenleaves | 8,031 | 0.31 ppb |
| Magnolia-Resolve Whisperwood | 6,867 | 1 ppb |
| Magnolia-The Meadows | 4,701 | 0.92 ppb |
| Magnolia-Lakeshore Estates | 4,146 | 1 ppb |
| Magnolia-Penn Mill Lakes | 1,152 | 0 (not detected) |
| Magnolia-Money Hills Estates | 825 | 0 (not detected) |
| Magnolia-River Park | 822 | 0 (not detected) |
| Magnolia - Brier Lake | 630 | 0 (not detected) |
| Magnolia-Grande Palms | 579 | 0 (not detected) |
Next steps for St. Louis, MO
Look up your address in Magnolia-Guste Island'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-Guste Island 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. Small systems behave differently: why small systems go over more often.