City of Houston Clean Water Act Settlement Information Sheet

(Washington, DC - August 27, 2019)  In a settlement agreement with the U.S. Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ), the city of Houston, Texas, has agreed to implement a comprehensive set of corrective measures and improvements to the city’s sewer system to resolve longstanding problems with sanitary sewer overflows (SSOs) and discharges into various water bodies of pollutants in excess of permitted limits from the city’s 39 wastewater treatment plants.

On this page:

Overview 

The city of Houston owns and operates one of the largest separate sewer systems in the country, consisting of 39 wastewater treatment plants (WWTPs) and a collection system with more than 6,100 miles of sewer pipe and 383 lift stations.

Violations

The Complaint alleges that the City of Houston violated Section 301 of the Clean Water Act and terms and conditions of its National Pollutant Discharge Elimination System permits, which set limits for how much of a certain pollutant an entity is allowed to discharge into a waterbody. Houston’s alleged violations include effluent limit exceedances, frequent discharges of raw sewage to waters of the United States and failure to prevent sanitary sewer overflows (SSOs) through proper operation and maintenance of its system.

Injunctive Relief

The proposed settlement includes specific requirements to address WWTP exceedances of permitted pollutant limits and SSOs, unintentional discharges of raw sewage from municipal sanitary sewers. The city will conduct a comprehensive assessment of its sanitary sewer system to identify defective sewer pipes and lift stations in poor condition.  The assessment results will be used to prioritize rehabilitation efforts aimed to prevent the occurrence of future SSOs.  The city will repair or replace no less than 150 miles of sewer pipe and associated manholes and renew or replace approximately 18 lift stations annually.  Houston has identified nine locations with deficient capacity to convey increases in flow through the system during wet weather.  Projects to address these capacity deficiencies are to be completed within the first 10 years of the settlement.  The City will also study whether discharges that occur from two permitted facilities outside of the 39 WWTPs during large storm events can meet treatment requirements imposed by the Clean Water Act.  If results indicate that achieving those treatment standards is not viable, then the city must eliminate those discharges. The City of Houston will develop and implement a capacity, management, operation, and maintenance program which includes comprehensive system cleaning and a grease and root control program to minimize SSOs caused by sewer blockages.  The City will also install more than 3,000 real-time sensors capable of sending alerts when conditions indicate a problem in the sewer system that may lead to an SSO. The total cost of implementing these measures is estimated to be $2 billion over the 15-year period to complete the injunctive relief. 

Pollutant Impacts

Through the implementation of the proposed Decree, the following estimated annual pollutant reductions will result:

• 9,468 pounds of total suspended solids;
• 9,063 pounds of biochemical oxygen demand;
• 1,471 pounds of total nitrogen; and
• 210 pounds of total phosphorus.

Health and Environmental Effects

• Total Suspended Solids (TSS) – TSS indicates the measure of suspended solids in wastewater, effluent or water bodies. High levels of TSS in a water body can diminish the amount of light that penetrates the water column and reduce photosynthesis and the production of oxygen.
• Biological Oxygen Demand (BOD) – BOD is an indirect measure of the biologically degradable material present in organic wastes. High BOD means there is an abundance of biologically degradable material that will consume oxygen from the water during the degradation process. It may take away oxygen that is needed for aquatic organisms to survive.
• Nutrients – Excess levels of nitrogen and phosphorus in waters can produce harmful algal blooms. These blooms contribute to the creation of hypoxia or “dead zones” in water bodies where dissolved oxygen levels are so low that most aquatic life cannot survive

Civil Penalty

The City of Houston will pay a civil penalty of $4,400,000 which will be split equally between the United States and the State of Texas.

Comment Period

The proposed settlement, lodged in the U.S. District Court for the Southern District of Texas, Houston Division, is subject to a 30-day public comment period and final court approval. Information on submitting comments is available at the Department of Justice website.

For More Information, Contact:

Carol DeMarco King, Attorney-Advisor
Municipal Enforcement Branch
Water Enforcement Division
1200 Pennsylvania Ave., NW
Washington, DC  20460
Phone: (202) 564-2412
king.carol@epa.gov

James Zimny
Municipal Enforcement Branch
Water Enforcement Division
1200 Pennsylvania Ave., NW
Washington, DC  20460
Phone: (202) 564-6551
zimny.james@epa.gov