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Heidelberg Materials US Cement LLC

Cement, Hydraulic, Mason City, Iowa. NPDES permit IA0072907, in force until May 31, 2031. Last 12 months: over a limit 5 times (last July 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (8 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
2 values over a limit, 12 required values missing, 2 of 12 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
October 2025Solids, total suspended, 30-day average46≤ 30 mg/L53%
October 2025Solids, total suspended, daily maximum46≤ 45 mg/L2%
December 2025Solids, total suspended, 30-day average31.18333≤ 30 mg/L4%
December 2025Solids, total suspended, daily maximum76≤ 45 mg/L69%
July 2026Solids, total suspended, daily maximum46.7≤ 45 mg/L4%

Limits in force (8)

ParameterStatisticLimitMonths
pHdaily minimum≥ 6 SUall year
pHdaily maximum≤ 9 SUall year
Solids, total suspended30-day average≤ 30 mg/Lall year
Solids, total suspendeddaily maximum≤ 45 mg/Lall year
Iron, total [as Fe]30-day average≤ 1 mg/Lall year
Iron, total [as Fe]daily maximum≤ 1 mg/Lall year
Iron, total [as Fe]30-day average≤ 6.67 lb/dall year
Iron, total [as Fe]daily maximum≤ 6.67 lb/dall year

How strict are these limits?

Cited limits by parameter: Iowa's rules and the federal ones.

Same industry: the 5 Stone, Clay, Glass and Concrete Products permits in Iowa.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/IA0072907 · MCP: https://passage-data.com/mcp