Monticello Water Supply, IA
Lead detected, under the action levels
Latest 90th-percentile lead: 3 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.
Monticello Water Supply at a glance
Monticello Water Supply serves about 4,040 people through 1,707 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 groundwater, in Jones County, Iowa. EPA system ID: IA5343098; phone on file: 319-465-3731. 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 Monticello Water Supply is 14 ppb across 4 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 3 ppb |
| 2022 | 3 ppb |
| 2019 | 10 ppb |
| 2016 | 14 ppb over 10 |
Where this result ranks
Of the 1,066 Iowa systems with a lead result, the median latest reading is 1.4 ppb; 4 are over 15 ppb right now and 36 have gone over at some point. Monticello Water Supply's 3 ppb sits at the 77th percentile in Iowa and the 82nd nationally (higher means more lead).
Other water systems in Jones County
10 other systems share Jones County; 1 of them has a higher latest lead result than Monticello Water Supply. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Anamosa Municipal Water Supply | 4,457 | 1 ppb |
| Anamosa State Penitentiary | 1,230 | 0 (not detected) |
| Olin Water Supply | 651 | 3.1 ppb |
| Wyoming Water System | 523 | 2.4 ppb |
| Oxford Junction Water Supply | 424 | 0.9 ppb |
| Martelle Water Works | 249 | 0 (not detected) |
| Onslow Water Supply | 201 | 0.6 ppb |
| Center Junction (Eiruss) | 100 | 0 (not detected) |
| Morley Municipal Water Supply | 98 | 0 (not detected) |
| Bacon Addition | 81 | 2 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Monticello, IA 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 Monticello Water Supply 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. The action level is dropping - the 10 ppb rule from 2027.