Brushy Creek Regional Wastewater Treatment System East Plant - 40 MGD Expansion - Environmental Information Document

The City of Round Rock is soliciting responses to an Environmental Information Document (EID) for the Brushy Creek Regional Wastewater Treatment System East Plant 40 MGD expansion project, with comments due May 27, 2026. The project spans Williamson County and includes the Cities of Austin, Cedar Park, and Leander as regional partners in the Brushy Creek Regional Wastewater System (BCRWWS).

The scope encompasses expansion of the Brushy Creek East Wastewater Treatment Plant from 30 MGD current capacity to 40 MGD final permitted capacity to serve projected regional population growth to 216,956 residents by 2040. Infrastructure additions include a fourth treatment train, influent lift stations, preliminary treatment units, aeration basins, clarifiers, filtration complexes, ultraviolet disinfection systems, and electrical facilities. The facility currently operates under TPDES Permit No. WQ0010264002, which authorizes discharge of treated effluent into Brushy Creek in the Brazos River Basin. The project site is partially located within the 100-year floodplain; design addresses flood resilience through elevated critical infrastructure and hydraulically isolated treatment trains. Dewatered sludge disposal continues at the Sheridan Composting Facility with overflow capacity at Williamson County Landfill.

The total estimated project cost is $117.57 million, funded through the Texas Water Development Board's Clean Water State Revolving Fund (CWSRF) with additional City of Round Rock contributions via cash or open market financing. Construction is scheduled to begin in mid-2027 and be completed by September 2030. Environmental review, permitting, and design are scheduled for completion by March 2026. The expansion is being pursued proactively to ensure compliance with Texas Administrative Code 305.126, which mandates construction initiation when a facility reaches 90 percent of its permitted average daily flow, expected by 2027.