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City of Mason City

Water Supply, Mason City, Iowa. NPDES permit IA0077305, in force until May 31, 2029. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due: About 15 days after each period: form A monthly (2 values)
Last report on file: August 2026
Oct 2024 – Sep 2025: 0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (2)

Parameter	Statistic	Limit	Months
pH	daily minimum	≥ 6.1 SU	all year
pH	daily maximum	≤ 9 SU	all year

How strict are these limits?

pH, daily minimum at least 6.1 SU — stricter than 52% of 423 other minor industrial and other permits in Iowa; 1% have the same limit

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

Same industry: the 48 Water Supply 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/IA0077305 · MCP: https://passage-data.com/mcp