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Great Lakes Aggregate-Sylvania

Construction Sand And Gravel, major discharger, South Rockwood, Michigan. NPDES permit MI0044491 expired Oct 1, 2018; its limits still apply. Last 12 months: over a limit 16 times (last September 2026), 110 required values missing. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 21 days after each period: form A monthly (20 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
25 values over a limit, 72 required values missing, 0 of 12 reports late

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

All 16 values over a limit
Period endingParameterReportedLimitOver by
October 2025Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
October 2025Hydrogen sulfide, daily maximum< 27≤ 6.4 ug/L322%
October 2025pH, daily maximum9.3≤ 9 SU—
November 2025Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
November 2025Hydrogen sulfide, daily maximum< 37≤ 6.4 ug/L478%
December 2025Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
December 2025Hydrogen sulfide, daily maximum< 22≤ 6.4 ug/L244%
January 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
February 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
March 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
April 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
May 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
June 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
July 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
August 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%
September 2026Hydrogen peroxide, monthly average< 50≤ 19 ug/L163%

Limits in force (33)

ParameterStatisticLimitMonths
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year
Conductivitymonthly averagereport only (umho/cm)all year
Conductivitydaily maximumreport only (umho/cm)all year
Hydrogen peroxidemonthly average≤ 19 ug/Lall year
Hydrogen peroxidedaily maximumreport only (ug/L)all year
Hydrogen peroxidemonthly average≤ 1.9 lb/dall year
Hydrogen peroxidedaily maximumreport only (lb/d)all year
Oxygen, dissolved [DO]daily minimum≥ 4 mg/Lall year
pHdaily minimum≥ 6.5 SUall year
pHdaily maximum≤ 9 SUall year
Solids, total suspendedmonthly average≤ 25 mg/Lall year
Solids, total suspendeddaily maximum≤ 45 mg/Lall year
Sulfide, dissolved, [as S]monthly averagereport only (ug/L)all year
Sulfide, dissolved, [as S]daily maximumreport only (ug/L)all year
Chloride [as Cl]daily maximumreport only (mg/L)all year
Sulfate, total [as SO4]monthly averagereport only (mg/L)all year
Sulfate, total [as SO4]daily maximumreport only (mg/L)all year
Strontium, total [as Sr]daily maximumreport only (ug/L)all year
Lithium, total [as Li]daily maximumreport only (ug/L)all year
Selenium, total [as Se]daily maximumreport only (ug/L)all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year
Solids, total dissolvedmonthly averagereport only (mg/L)all year
Solids, total dissolveddaily maximumreport only (mg/L)all year
Hydrogen sulfidemonthly average≤ .69 ug/Lall year
Hydrogen sulfidedaily maximum≤ 6.4 ug/Lall year
Hydrogen sulfidemonthly average≤ .069 lb/dall year
Hydrogen sulfidedaily maximum≤ .64 lb/dall year
Outfall observation,visual, y/n responsevaluereport only (N=0;Y=1)all year
TU Static 24 Hr Acute Pimephales promelasdaily maximumreport only (tox acute)all year
Static 48 Hr Chronic Pimphales Promelasmonthly average≤ 2.1 tox chronicall year
Static 48 Hr Chronic Pimphales Promelasdaily maximumreport only (tox chronic)all year

How strict are these limits?

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

Same industry: the 17 Mining and Quarrying of Nonmetallic Minerals permits in Michigan.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MI0044491 · MCP: https://passage-data.com/mcp