Rock Valley Rural Water District, IA
Lead detected, under the action levels
Latest 90th-percentile lead: 2.4 ppb (monitoring period 2025-2025). 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.
Rock Valley Rural Water District at a glance
Rock Valley Rural Water District serves about 2,250 people through 900 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in Sioux County, Iowa. EPA system ID: IA8482701; phone on file: 712-476-5246. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Rock Valley Rural Water District's lead record
That is down 2 ppb from 4.4 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Rock Valley Rural Water District is 4.9 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2.4 ppb |
| 2024 | 4.4 ppb |
| 2021 | 4.9 ppb |
| 2018 | 4 ppb |
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. Rock Valley Rural Water District's 2.4 ppb sits at the 71st percentile in Iowa and the 77th nationally (higher means more lead).
Neighbouring systems
14 other systems share Sioux County; 3 of them have a higher latest lead result than Rock Valley Rural Water District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Sioux Center Municipal Water Department | 8,231 | 4.4 ppb |
| Orange City Municipal Water Department | 6,267 | 0 (not detected) |
| Southern Sioux County Rural Water | 5,420 | 2.1 ppb |
| Rock Valley Water Supply | 4,059 | 2 ppb |
| Rural Water System #1 | 3,428 | 1.2 ppb |
| Hawarden Water Supply | 2,700 | 0 (not detected) |
| Hull Water Supply | 2,384 | 1.8 ppb |
| Alton Municipal Water Department | 1,248 | 0.87 ppb |
| Hospers Municipal Water Dept | 718 | 6.1 ppb |
| Boyden Municipal Water Supply | 709 | 2.2 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Rock Valley, 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 Rock Valley Rural Water District 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. Systems that went over once often dip back under; here is what that means.