Passage Data · Check a report · Use it from your AI

Montana Aviation Research Co

Aircraft, Saint Marie, Montana. NPDES permit MT0029980, in force until Mar 31, 2027. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due: About 28 days after each period: form A monthly (11 values)
Renewal application due: Oct 2, 2026 · 180 days before expiry; your permit may set another date
Last report on file: August 2026
Oct 2024 – Sep 2025: 0 values over a limit, 22 required values missing, 4 of 12 reports late

Limits in force (11)

Parameter	Statistic	Limit	Months
Flow rate	monthly average	report only (MGD)	all year
Flow rate	daily maximum	report only (MGD)	all year
pH	minimum	≥ 6 SU	all year
pH	maximum	≤ 9 SU	all year
Solids, total suspended	monthly average	≤ 30 mg/L	all year
Solids, total suspended	daily maximum	≤ 45 mg/L	all year
Aluminum, dissolved [as Al]	monthly average	report only (mg/L)	all year
Aluminum, dissolved [as Al]	daily maximum	≤ .75 mg/L	all year
Chlorine, total residual	monthly average	report only (mg/L)	all year
Chlorine, total residual	daily maximum	≤ .099 mg/L	all year
Duration of discharge	value	report only (d)	all year

How strict are these limits?

Aluminum, dissolved [as Al], daily maximum .75 mg/L — stricter than 93% of 49 other minor industrial and other permits nationwide; 2% have the same limit
Solids, total suspended, daily maximum 45 mg/L — stricter than 66% of 21 other minor industrial and other permits in Montana; 10% have the same limit
Solids, total suspended, monthly average 30 mg/L — stricter than 44% of 25 other minor industrial and other permits in Montana; 40% have the same limit

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

Check this month's numbers Email me before each report is due

· Save this facility as a site · Superfund sites nearby · Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MT0029980 · MCP: https://passage-data.com/mcp