Nampa City Of, ID
Lead detected, under the action levels
Latest 90th-percentile lead: 1 ppb (monitoring period 2025-2027). 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.
About Nampa City Of
Nampa City Of serves about 100,200 people through 38,361 service connections, which makes it a very large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Canyon County, Idaho. EPA system ID: ID3140080; phone on file: 208-468-5860. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
Against the period ending 2024 (2 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Nampa City Of is 2 ppb across 7 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2027 | 1 ppb |
| 2024 | 2 ppb |
| 2021 | 0 (not detected) |
| 2018 | 0 (not detected) |
| 2017 | 0 (not detected) |
| 2017 | 0 (not detected) |
| 2016 | 0 (not detected) |
Against other Idaho systems
Of the 763 Idaho systems with a lead result, the median latest reading is 1 ppb; 3 are over 15 ppb right now and 46 have gone over at some point. Nampa City Of's 1 ppb sits at the 56th percentile in Idaho and the 56th nationally (higher means more lead).
Neighbouring systems
82 other systems share Canyon County; 36 of them have a higher latest lead result than Nampa City Of. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Caldwell City Of | 78,740 | 0 (not detected) |
| Middleton City Of | 13,190 | 2 ppb |
| Parma City Of | 2,250 | 1 ppb |
| Wilder City Of | 1,690 | 5 ppb |
| Caldwell Housing Authority | 1,100 | 9 ppb |
| Greenleaf City Of | 846 | 2 ppb |
| Melba City Of | 648 | 3 ppb |
| Notus City Of | 539 | 2 ppb |
| Shalimar Subd | 370 | 1 ppb |
| Belle Aire Acres 2 | 350 | 1 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Nampa, ID 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 Nampa City Of 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.