Leander City Council voted unanimously Oct. 18 to approve a new wastewater service agreement with the city of Round Rock.

The agreement states the city of Leander will purchase 4.23 million gallons per day of treatment capacity in an expansion project of the Brushy Creek Regional Wastewater System, or BCRWS.

Parts of BCRWS are owned by Round Rock, Cedar Park and Austin. The city of Leander has rented capacity in Round Rock’s east wastewater treatment plant since 2010. At that time, Leander agreed to rent 1 million gallons per day of capacity. As the city has grown, it has had to request more; in 2016, Leander City Council approved an amendment to increase the rental amount to 1.5 million gallons per day of treatment capacity at $21,088.13 per month.

The BCRWS east regional wastewater treatment plant in Round Rock is being expanded by 10 million gallons per day of capacity because wastewater flows are nearing the plant's design limits, according to city documents.

Until the expansion of the plant is complete, Leander will continue to rent treatment capacity from Round Rock. The expansion project is estimated to cost $90 million—with Leander paying about 42 percent—and is expected to be complete in 2024 or 2025, according to city documents.