Nuevo Laredo, Tamaulipas, Mexico

Wastewater Collection System Improvements –Disconnection from Storm Water Sewer Nuevo Laredo, Tamaulipas

Status: Completed


COMAPA is responsible for providing water and wastewater services to area residents. The primary source of water supply for the city is the Rio Grande River. In 2011, water coverage in Nuevo Laredo was estimated at 98% of the population and wastewater collection at 96%, while wastewater treatment coverage was estimated at 79%. Treatment is provided through two plants: the International Wastewater Treatment Plant (WWTP) with a 29.7 million gallon a day (mgd) capacity; and the Northwest WWTP with 4.6 mgd capacity.

Many of the old wastewater mains have exceeded their useful life and are deteriorated, giving rise to frequent collapses throughout the system. The collapse of these lines has resulted in raw sewage leaking and pooling in local streets, exposing residents to sewer contamination. In some cases, as a temporary fix, the collapsed lines were interconnected with the stormwater system, resulting in raw sewage being directly discharged into the Rio Grande River.

To remedy this situation, COMAPA has developed a project to replace the collapsed sewer lines and eliminate any interconnection with the following storm drains: Niños Heroes, Lincoln, Guatemala, 5 de Febrero, Monterrey, and 20 de Noviembre.


The project consists of rehabilitating and replacing collapsed concrete sewer lines and disconnecting any interconnections there may be with storm water drains. The project entails the construction of approximately 11,777 meters (38,638 ft) of sewer lines and 2,491 meters (8,173 ft.) of subcollectors of varying diameter.

The wastewater will discharge by gravity into an existing collector that will convey the flows to the International Wastewater Treatment Plant, which has sufficient capacity to handle the additional flows.


Implementation of the project will prevent untreated wastewater discharges into the Rio Grande River, which will reduce environmental contamination and the risk of waterborne diseases, thus providing a safer and healthier source of water for the city, as well as for downstream users. Specifically, an estimated 5.2 million gallons a day of wastewater will be collected and treated prior to being discharged into the river.

Project Financing

Total Project Cost US 3.93M
NADBank Funding US 2.5M - NADBank Grant: BEIF