Nitrate levels in Iowa water remained high through fall, data show

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Nitrate concentrations, exacerbated by a wet spring that followed years of dry conditions, reached near record highs in Iowa rivers this summer.

Concentrations are typically elevated in the summer. The past several years, nitrates have dropped to near-zero concentrations in late summer through early winter. But this year, concentrations in rivers and in central Iowa’s drinking water have remained high.

Water quality advocates say the 2025 trend is further evidence that the state should prioritize long-term funding for water quality monitoring. Monitoring that included a longer timeline, they say, would show if these trends were consistent with similar weather patterns in the past, or indicati