Northwest WWTP
5423 Mangum Rd, Houston, TX 77091 · Harris County · Publicly Owned Treatment Works
- Average flow
- 19.83 MGD
- Design flow
- 18 MGD
- NPDES permit
- TX0063011
- Effective
- Permit expires
- August 2030
- Population served
- 100,000
- CWNS 2022
Northwest WWTP is a publicly owned wastewater treatment works in Houston, Harris County, Texas treating an average of 19.83 million gallons per day against a permitted design capacity of 18 MGD, serving about 100,000 residents. It discharges under NPDES permit TX0063011 (effective), which expires in August 2030, with 16 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in April 2021.
Treatment technology
One treatment structure or unit process identified at Northwest WWTP.
Available with a free Klarifi account
See the full treatment train at Northwest WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 16
- Effluent violations
- 16
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for Northwest WWTP in EPA's ICIS system.
- Formal actions
- 1
- 0 since FY2020
- Penalties assessed
- $4.4M
- all cases
- Compliance actions
- $2,000M
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Apr 2021
Houston, City of
Judicial case · CWA, NPDES Permit Violations · Final Order With Penalty · Penalty $4.4M · Compliance actions $2,000M · The case also names 35 other plants, and its amounts cover all of them
EPA's description of the case:
“City of Houston was issued the Consent Decree for both permit effluent violations and Sanitary Sewer Overflows.”
Source: EPA ECHO, civil enforcement case 06-2010-1780.
Full case history with a free Klarifi account
Every action against Northwest WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Capital improvement projects in Houston
Houston's capital improvement plan lists 22 water, sewer and wastewater line items worth $1.3B starting 2025–2025. The largest budgeted items are shown here.
All water and sewer capital projects in Houston →
| Project | Budget | Years |
|---|---|---|
| Wastewater Treatment Plant Improvements | $353,943,200 | 2025–2025 |
| Wastewater Treatment Plant Consolidation | $166,807,000 | 2025–2025 |
| Surface Water Transmission Program | $132,740,144 | 2025–2025 |
| Neighborhood Sewer Rehab Program | $96,000,000 | 2025–2025 |
| Pump Station Program | $87,851,600 | 2025–2025 |
Full project details — scope, funding source, engineering consultant and the decision-makers behind each project — are available in Klarifi, along with similar wastewater capital projects in other cities.
Key contacts
39 verified contacts for Northwest WWTP, with validated emails and direct phone numbers.
Unlock 39 verified contacts (36 more than shown)
Names, validated emails and direct phone numbers for decision-makers at Northwest WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Texas
Houston · 3 mi away
4.42 MGD
Houston · 4 mi away
0.33 MGD
Houston · 4 mi away
0.57 MGD
Houston · 4 mi away
0.52 MGD
Houston · 4 mi away
0.12 MGD
Houston · 5 mi away
0.43 MGD
Houston · 5 mi away
1.27 MGD
Houston · 5 mi away
0.59 MGD
Northwest WWTP: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026; facility record last updated May 27, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Sludge dewatering · Biological nutrient removal · all terms