Harris County Mud 371 — NPDES permit TX0117129: limits, due date and EPA's record

Sewage treatment plant, Cypress, Texas. NPDES permit TX0117129, in force until Apr 11, 2030. Last 12 months: over a limit 2 times (last May 2026). Source: EPA ECHO, Oct 22, 2026.

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

Period ending	Parameter	Reported	Limit	Over by
February 2026	Solids, total suspended, single grab sample	64.5 mg/L	≤ 60 mg/L	8%
May 2026	Solids, total suspended, daily average	17.9 mg/L	≤ 15 mg/L	19%

Limits in force (19)

Parameter	Statistic	Limit	Months
Oxygen, dissolved [DO]	monthly minimum	≥ 4 mg/L	Jan, Feb, Mar, Nov, Dec
Oxygen, dissolved [DO]	monthly minimum	≥ 6 mg/L	Apr–Oct
pH	minimum	≥ 6 SU	all year
pH	maximum	≤ 9 SU	all year
Solids, total suspended	daily average	≤ 15 mg/L	all year
Solids, total suspended	single grab sample	≤ 60 mg/L	all year
Solids, total suspended	daily average	≤ 31 lb/d	all year
Nitrogen, ammonia total [as N]	daily average	≤ 3 mg/L	all year
Nitrogen, ammonia total [as N]	single grab sample	≤ 15 mg/L	all year
Nitrogen, ammonia total [as N]	daily average	≤ 6.3 lb/d	all year
Flow, in conduit or thru treatment plant	daily average	≤ .25 MGD	all year
Flow, in conduit or thru treatment plant	daily maximum	report only (MGD)	all year
Chlorine, total residual	monthly minimum	≥ 1 mg/L	all year
Chlorine, total residual	monthly maximum	≤ 4 mg/L	all year
E. coli	daily average	≤ 63 CFU/100mL	all year
E. coli	single grab sample	≤ 200 CFU/100mL	all year
BOD, carbonaceous [5 day, 20 C]	daily average	≤ 10 mg/L	all year
BOD, carbonaceous [5 day, 20 C]	single grab sample	≤ 35 mg/L	all year
BOD, carbonaceous [5 day, 20 C]	daily average	≤ 21 lb/d	all year

How strict are these limits?

Your permit document is the final word. As JSON: /api/v1/permits/TX0117129 · MCP: https://passage-data.com/mcp