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Tap water quality report

Rock Valley Water Supply

EPA monitoring tested this supplier for 82 contaminants and detected 16. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

82
contaminants tested
16
detected
4,059
people served
63
health-based violations
Iowa rankingsLead in IowaPFAS in Iowa
Water source
Ground water
Ownership
Local government
Counties served
Sioux

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

63
health-based violations
90
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2002-08-01 → 2002-08-31
MCL Health-based Resolved 2002-08-01 → 2002-08-31
MCL Health-based Resolved 2002-08-01 → 2002-08-31
MCL Health-based Resolved 2002-08-01 → 2002-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31
MCL Health-based Resolved 2000-08-01 → 2000-08-31

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Fluoride
1020 µg/L 26%
of the EPA limit 4000 µg/L
 96/96 SYR4 2012–2019
Nitrate
9800 µg/L 98%
of the EPA limit 10000 µg/L
 64/64 SYR4 2012–2019
Copper
1600 µg/L 123%
of the EPA limit, in the worst sample — 1300 µg/L
 50/50 SYR4 2012–2018
Lead
140 µg/L 933%
of the EPA limit, in the worst sample — 15 µg/L
 33/50 SYR4 2012–2018
Lead
0.0020 mg/L 13%
of the EPA limit 0.0150 mg/L
 13/13 LCR 2025
Bromodichloromethane
4.3 µg/L
No EPA limit set
 7/7 SYR4 2013–2019
Bromoform
1.5 µg/L
No EPA limit set
 7/7 SYR4 2013–2019
Chloroform
3.5 µg/L
No EPA limit set
 7/7 SYR4 2013–2019
Dibromoacetic Acid
3 µg/L
No EPA limit set
 7/7 SYR4 2013–2019
Dibromochloromethane
4.4 µg/L
No EPA limit set
 7/7 SYR4 2013–2019
TTHM
13 µg/L 16%
of the EPA limit 80 µg/L
 7/7 SYR4 2013–2019
Dichloroacetic Acid
2 µg/L
No EPA limit set
 6/7 SYR4 2013–2019
Total Haloacetic Acids (HAA5)
7 µg/L 12%
of the EPA limit 60 µg/L
 2/7 SYR4 2013–2019
Trichloroacetic Acid
2 µg/L
No EPA limit set
 2/7 SYR4 2013–2019
Lithium
14 µg/L
No EPA limit set
 2/2 UCMR-5 2025
Monobromoacetic Acid
2 µg/L
No EPA limit set
 1/7 SYR4 2013–2019
66 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAtrazineBenzeneBenzo(A)PyreneChlorobenzeneCarbon TetrachlorideCombined Radium (-226 And -228)DichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylbenzeneGlyphosateHfpo-DaLassoMonochloroacetic AcidNetfosaaNfdhaNmefosaaPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneTolueneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
ROCK VALLEY WATER SUPPLY
Phone
712-470-1936
Email
shanevb@cityofrockvalley.com

Frequently asked questions about Rock Valley Water Supply

Is Rock Valley Water Supply tap water safe to drink?

EPA monitoring detected 16 contaminants in Rock Valley Water Supply's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Rock Valley Water Supply's water?

EPA monitoring detected Fluoride, Nitrate, Copper, Lead, Lead, and others. The full list with the level and data source for each is above.

How many people does Rock Valley Water Supply serve?

Rock Valley Water Supply reports serving 4,059 people in Iowa, per its EPA record.

Has Rock Valley Water Supply had any water quality violations?

The EPA has 90 violations on file for Rock Valley Water Supply, of which 63 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.