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Costilla County Water and Sanitation District

Sewage treatment plant, Costilla County, Colorado. NPDES permit CO0036528 expired Jun 30, 2019; its limits still apply. Last 12 months: over a limit 2 times (last August 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A monthly (17 values), outfall 300 form I monthly (10 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 2 of 24 reports late

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

Period endingParameterReportedLimitOver by
August 2026BOD, 5-day, 20 deg. C, 30-day average44 mg/L≤ 30 mg/L47%
August 2026Nitrogen, ammonia total [as N], 30-day average18.1 mg/L≤ 6.6 mg/L174%

Limits in force (100)

ParameterStatisticLimitMonthsOutfall
BOD, 5-day, 20 deg. C30-day average≤ 30 mg/LApr–Sep001
BOD, 5-day, 20 deg. C30-day average≤ 30 mg/LJan, Feb, Mar, Oct, Nov, Dec001
BOD, 5-day, 20 deg. Cmaximum 7-day average≤ 45 mg/LApr–Sep001
BOD, 5-day, 20 deg. Cmaximum 7-day average≤ 45 mg/LJan, Feb, Mar, Oct, Nov, Dec001
BOD, 5-day, 20 deg. C30-day average≤ 54 lb/dApr–Sep001
BOD, 5-day, 20 deg. C30-day average≤ 33 lb/dJan, Feb, Mar, Oct, Nov, Dec001
pHminimum≥ 6.5 SUall year001
pHmaximum≤ 9 SUall year001
Solids, total suspended30-day average≤ 75 mg/Lall year001
Solids, total suspendedmaximum 7-day average≤ 110 mg/Lall year001
Nitrogen, ammonia total [as N]30-day average≤ 46 mg/LJan001
Nitrogen, ammonia total [as N]30-day average≤ 43 mg/LFeb001
Nitrogen, ammonia total [as N]30-day average≤ 32 mg/LMar001
Nitrogen, ammonia total [as N]30-day average≤ 27.6 mg/LApr001
Nitrogen, ammonia total [as N]30-day average≤ 19.1 mg/LMay001
Nitrogen, ammonia total [as N]30-day average≤ 18.6 mg/LJun001
Nitrogen, ammonia total [as N]30-day average≤ 19 mg/LJul001
Nitrogen, ammonia total [as N]30-day averagereport only (mg/L)Aug001
Nitrogen, ammonia total [as N]30-day average≤ 6.2 mg/LSep001
Nitrogen, ammonia total [as N]30-day average≤ 22.2 mg/LOct001
Nitrogen, ammonia total [as N]30-day average≤ 24.2 mg/LNov001
Nitrogen, ammonia total [as N]30-day average≤ 34 mg/LDec001
Nitrogen, ammonia total [as N]30-day average≤ 6.6 mg/LAug001
Nitrogen, ammonia total [as N]daily maximum≤ 83 mg/LJan001
Nitrogen, ammonia total [as N]daily maximum≤ 67 mg/LFeb001
Nitrogen, ammonia total [as N]daily maximum≤ 58 mg/LMar001
Nitrogen, ammonia total [as N]daily maximum≤ 128 mg/LApr001
Nitrogen, ammonia total [as N]daily maximum≤ 106 mg/LMay001
Nitrogen, ammonia total [as N]daily maximum≤ 132 mg/LJun001
Nitrogen, ammonia total [as N]daily maximum≤ 55 mg/LJul001
Nitrogen, ammonia total [as N]daily maximum≤ 51 mg/LAug001
Nitrogen, ammonia total [as N]daily maximum≤ 51 mg/LSep001
Nitrogen, ammonia total [as N]daily maximum≤ 55 mg/LOct001
Nitrogen, ammonia total [as N]daily maximum≤ 54 mg/LNov001
Nitrogen, ammonia total [as N]daily maximum≤ 58 mg/LDec001
Nitrogen, ammonia total [as N]daily maximum≤ 51 mg/LAug001
Oil and greaseinstantaneous maximum≤ 10 mg/Lall year001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDFeb001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDSep001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDNov001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDJan001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDMay001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDApr001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDJul001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDAug001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDMar001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDOct001
Flow, in conduit or thru treatment plant30-day average≤ .216 MGDJun001
Flow, in conduit or thru treatment plant30-day average≤ .13 MGDDec001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Feb001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Sep001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Nov001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Jan001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)May001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Apr001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Jul001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Aug001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Mar001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Oct001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Jun001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)Dec001
Chlorine, total residual30-day average≤ .11 mg/LOct001
Chlorine, total residual30-day average≤ .11 mg/LMar001
Chlorine, total residual30-day average≤ .11 mg/LNov001
Chlorine, total residual30-day average≤ .066 mg/LSep001
Chlorine, total residual30-day average≤ .066 mg/LJul001
Chlorine, total residual30-day average≤ .066 mg/LApr001
Chlorine, total residual30-day average≤ .066 mg/LJun001
Chlorine, total residual30-day average≤ .11 mg/LFeb001
Chlorine, total residual30-day average≤ .066 mg/LAug001
Chlorine, total residual30-day average≤ .11 mg/LJan001
Chlorine, total residual30-day average≤ .066 mg/LMay001
Chlorine, total residual30-day average≤ .11 mg/LDec001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LOct001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LMar001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LNov001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LSep001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LJul001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LApr001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LJun001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LFeb001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LAug001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LJan001
Chlorine, total residualinstantaneous maximum≤ .13 mg/LMay001
Chlorine, total residualinstantaneous maximum≤ .21 mg/LDec001
E. coli30-day geometric mean≤ 1920 #/100mLJan, Feb, Mar, Oct, Nov, Dec001
E. coli30-day geometric mean≤ 1156 #/100mLApr–Sep001
E. colimaximum 7-day geometric mean≤ 4000 #/100mLJan, Feb, Mar, Oct, Nov, Dec001
E. colimaximum 7-day geometric mean≤ 2040 #/100mLApr–Sep001
Oil and grease visualinstantaneous maximumreport only (N=0;Y=1)all year001
Plant capacity fact. percent of capacity30-day averagereport only (%)all year300
Plant capacity fact. percent of capacity30-day averagereport only (%)all year300
BOD, 5-day, 20 deg. C30-day averagereport only (mg/L)all year300
BOD, 5-day, 20 deg. Cmaximum 7-day averagereport only (mg/L)all year300
BOD, 5-day, 20 deg. C30-day averagereport only (lb/d)all year300
BOD, 5-day, 20 deg. Cmaximum 7-day averagereport only (lb/d)all year300
Solids, total suspended30-day averagereport only (mg/L)all year300
Solids, total suspendedmaximum 7-day averagereport only (mg/L)all year300
Flow, in conduit or thru treatment plant30-day averagereport only (MGD)all year300
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year300

How strict are these limits?

Cited limits by parameter: Colorado'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/CO0036528 · MCP: https://passage-data.com/mcp