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Sewage treatment plant, Ronan, Montana. NPDES permit MT0021474, in force until Jun 30, 2027. Last 12 months: over a limit 8 times (last June 2026), 1 of 31 reports late. Source: EPA ECHO, Oct 22, 2026.
| Period ending | Parameter | Reported | Limit | Over by |
|---|---|---|---|---|
| December 2025 | Nitrogen, ammonia total [as N], 30-day average | 10.2 mg/L | ≤ 3.78 mg/L | 170% |
| January 2026 | Nitrogen, ammonia total [as N], 30-day average | 15.9 mg/L | ≤ 3.78 mg/L | 321% |
| January 2026 | Nitrogen, ammonia total [as N], daily maximum | 15.9 mg/L | ≤ 15.4 mg/L | 3% |
| February 2026 | Nitrogen, ammonia total [as N], 30-day average | 18.8 mg/L | ≤ 3.78 mg/L | 397% |
| February 2026 | Nitrogen, ammonia total [as N], daily maximum | 18.8 mg/L | ≤ 15.4 mg/L | 22% |
| March 2026 | Nitrogen, ammonia total [as N], 30-day average | 16.6 mg/L | ≤ 3.78 mg/L | 339% |
| March 2026 | Nitrogen, ammonia total [as N], daily maximum | 16.6 mg/L | ≤ 15.4 mg/L | 8% |
| June 2026 | Nitrogen, ammonia total [as N], 30-day average | 5.1 mg/L | ≤ 3.78 mg/L | 35% |
| Parameter | Statistic | Limit | Months | Outfall |
|---|---|---|---|---|
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | 001 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | 001 |
| Oxygen, dissolved [DO] | daily minimum | report only (mg/L) | all year | 001 |
| Oxygen, dissolved [DO] | 30-day average | report only (mg/L) | all year | 001 |
| BOD, 5-day, 20 deg. C | 30-day average | ≤ 30 mg/L | all year | 001 |
| BOD, 5-day, 20 deg. C | daily maximum | ≤ 45 mg/L | all year | 001 |
| BOD, 5-day, 20 deg. C | 30-day average | report only (mg/L) | all year | 001 |
| BOD, 5-day, 20 deg. C | daily maximum | report only (mg/L) | all year | 001 |
| pH | instantaneous minimum | ≥ 6.5 SU | all year | 001 |
| pH | instantaneous maximum | ≤ 8.5 SU | all year | 001 |
| Solids, total suspended | 30-day average | ≤ 30 mg/L | all year | 001 |
| Solids, total suspended | daily maximum | ≤ 45 mg/L | all year | 001 |
| Solids, total suspended | 30-day average | report only (mg/L) | all year | 001 |
| Solids, total suspended | daily maximum | report only (mg/L) | all year | 001 |
| Oil & Grease | daily maximum | ≤ 10 mg/L | all year | 001 |
| Nitrogen, total [as N] | 30-day average | report only (mg/L) | all year | 001 |
| Nitrogen, total [as N] | daily maximum | report only (mg/L) | all year | 001 |
| Nitrogen, ammonia total [as N] | 30-day average | ≤ 3.78 mg/L | all year | 001 |
| Nitrogen, ammonia total [as N] | daily maximum | ≤ 15.4 mg/L | all year | 001 |
| Phosphorus, total [as P] | 30-day average | report only (mg/L) | all year | 001 |
| Phosphorus, total [as P] | daily maximum | report only (mg/L) | all year | 001 |
| Floating solids, waste or visible foam-visual | instantaneous maximum | ≤ 0 N=0;Y=1 | all year | 001 |
| Flow, in conduit or thru treatment plant | 30-day average | report only (MGD) | all year | 001 |
| Flow, in conduit or thru treatment plant | daily maximum | report only (MGD) | all year | 001 |
| E. coli | 30-day average | ≤ 126 #/100mL | all year | 001 |
| E. coli | daily maximum | ≤ 252 #/100mL | all year | 001 |
| Nitrogen, Kjeldahl Total | 30-day average | report only (mg/L) | all year | 001 |
| Nitrogen, Kjeldahl Total | daily maximum | report only (mg/L) | all year | 001 |
| Nitrite Plus Nitrate Total | 30-day average | report only (mg/L) | all year | 001 |
| Nitrite Plus Nitrate Total | daily maximum | report only (mg/L) | all year | 001 |
| Solids, total dissolved [TDS] | 30-day average | report only (mg/L) | all year | 001 |
| Solids, total dissolved [TDS] | daily maximum | report only (mg/L) | all year | 001 |
| Coliform, fecal general | 30-day average | ≤ 200 #/100mL | all year | 001 |
| Coliform, fecal general | daily maximum | ≤ 400 #/100mL | all year | 001 |
| BOD, 5-day, percent removal | minimum | ≥ 85 % | all year | 001 |
| Solids, suspended percent removal | minimum | ≥ 85 % | all year | 001 |
| Oil and grease visual | instantaneous maximum | ≤ 0 N=0;Y=1 | all year | 001 |
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | CC01 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | CC01 |
| pH | instantaneous minimum | report only (SU) | all year | CC01 |
| pH | instantaneous maximum | report only (SU) | all year | CC01 |
| Nitrogen, ammonia total [as N] | 30-day average | report only (mg/L) | all year | CC01 |
| Nitrogen, ammonia total [as N] | daily maximum | report only (mg/L) | all year | CC01 |
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | IM01 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | IM01 |
| Oxygen, dissolved [DO] | daily minimum | report only (mg/L) | all year | IM01 |
| Oxygen, dissolved [DO] | 30-day average | report only (mg/L) | all year | IM01 |
| BOD, 5-day, 20 deg. C | 30-day average | report only (mg/L) | all year | IM01 |
| BOD, 5-day, 20 deg. C | daily maximum | report only (mg/L) | all year | IM01 |
| pH | instantaneous minimum | report only (SU) | all year | IM01 |
| pH | instantaneous maximum | report only (SU) | all year | IM01 |
| Nitrogen, ammonia total [as N] | 30-day average | report only (mg/L) | all year | IM01 |
| Nitrogen, ammonia total [as N] | daily maximum | report only (mg/L) | all year | IM01 |
| Nitrogen, nitrate total [as N] | 30-day average | report only (mg/L) | all year | IM01 |
| Nitrogen, nitrate total [as N] | daily maximum | report only (mg/L) | all year | IM01 |
| BOD, carbonaceous [5 day, 20 C] | 30-day average | report only (mg/L) | all year | IM01 |
| BOD, carbonaceous [5 day, 20 C] | daily maximum | report only (mg/L) | all year | IM01 |
| BOD, 5-day, percent removal | minimum | report only (%) | all year | IM01 |
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | IM02 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | IM02 |
| Oxygen, dissolved [DO] | daily minimum | report only (mg/L) | all year | IM02 |
| Oxygen, dissolved [DO] | 30-day average | report only (mg/L) | all year | IM02 |
| BOD, 5-day, 20 deg. C | 30-day average | report only (mg/L) | all year | IM02 |
| BOD, 5-day, 20 deg. C | daily maximum | report only (mg/L) | all year | IM02 |
| pH | instantaneous minimum | report only (SU) | all year | IM02 |
| pH | instantaneous maximum | report only (SU) | all year | IM02 |
| Nitrogen, ammonia total [as N] | 30-day average | report only (mg/L) | all year | IM02 |
| Nitrogen, ammonia total [as N] | daily maximum | report only (mg/L) | all year | IM02 |
| Nitrogen, nitrate total [as N] | 30-day average | report only (mg/L) | all year | IM02 |
| Nitrogen, nitrate total [as N] | daily maximum | report only (mg/L) | all year | IM02 |
| BOD, carbonaceous [5 day, 20 C] | 30-day average | report only (mg/L) | all year | IM02 |
| BOD, carbonaceous [5 day, 20 C] | daily maximum | report only (mg/L) | all year | IM02 |
| BOD, 5-day, percent removal | minimum | report only (%) | all year | IM02 |
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | IM03 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | IM03 |
| Oxygen, dissolved [DO] | daily minimum | report only (mg/L) | all year | IM03 |
| Oxygen, dissolved [DO] | 30-day average | report only (mg/L) | all year | IM03 |
| BOD, 5-day, 20 deg. C | 30-day average | report only (mg/L) | all year | IM03 |
| BOD, 5-day, 20 deg. C | daily maximum | report only (mg/L) | all year | IM03 |
| pH | instantaneous minimum | report only (SU) | all year | IM03 |
| pH | instantaneous maximum | report only (SU) | all year | IM03 |
| Nitrogen, ammonia total [as N] | 30-day average | report only (mg/L) | all year | IM03 |
| Nitrogen, ammonia total [as N] | daily maximum | report only (mg/L) | all year | IM03 |
| Nitrogen, nitrate total [as N] | 30-day average | report only (mg/L) | all year | IM03 |
| Nitrogen, nitrate total [as N] | daily maximum | report only (mg/L) | all year | IM03 |
| BOD, carbonaceous [5 day, 20 C] | 30-day average | report only (mg/L) | all year | IM03 |
| BOD, carbonaceous [5 day, 20 C] | daily maximum | report only (mg/L) | all year | IM03 |
| BOD, 5-day, percent removal | minimum | report only (%) | all year | IM03 |
| Temperature, water deg. centigrade | instantaneous minimum | report only (deg C) | all year | RW01 |
| Temperature, water deg. centigrade | instantaneous maximum | report only (deg C) | all year | RW01 |
| pH | instantaneous minimum | report only (SU) | all year | RW01 |
| pH | instantaneous maximum | report only (SU) | all year | RW01 |
| Nitrogen, ammonia total [as N] | 30-day average | report only (mg/L) | all year | RW01 |
| Nitrogen, ammonia total [as N] | daily maximum | report only (mg/L) | all year | RW01 |
Cited limits by parameter: Montana's rules and the federal ones.
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On EPA ECHO: Facility report · DMR history
Your permit document is the final word. As JSON: /api/v1/permits/MT0021474 · MCP: https://passage-data.com/mcp