Castleford City Of, ID
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.
Castleford City Of at a glance
Castleford City Of serves about 275 people through 115 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Twin Falls County, Idaho. EPA system ID: ID5420010; phone on file: 208-537-6544. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
That is down 3 ppb from 3 ppb in the period ending 2022. The highest 90th-percentile result EPA holds for Castleford City Of is 3 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2022 | 3 ppb |
| 2019 | 1 ppb |
| 2016 | 3 ppb |
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. Castleford City Of's reported as 0 (not detected) sits at the 26th percentile in Idaho and the 18th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in Twin Falls County
12 other systems share Twin Falls County; 4 of them have a higher latest lead result than Castleford City Of. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Twin Falls City Of | 56,121 | 0 (not detected) |
| Kimberly City Of | 5,359 | 0 (not detected) |
| Buhl City Of | 4,518 | 0 (not detected) |
| Filer Water Works | 2,858 | 2.77 ppb |
| Hansen City Of | 1,200 | 0 (not detected) |
| Kanaka Rapids Ranch Water System Inc | 240 | 0 (not detected) |
| Hollister City Of | 220 | 1 ppb |
| Rock Ledge Estates | 150 | 0 (not detected) |
| Meander Point Subd | 140 | 0 (not detected) |
| Murtaugh City Of | 130 | 0 (not detected) |
Your move
Look up your address in Castleford City Of'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 Castleford 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. What a 90th-percentile result does and does not tell you: how to read a lead result. A zero today does not rule out a jump later - the rules are tightening in 2027.