La Union, New Mexico, USA

Construction of Wastewater Collection and Treatment System for La Union, New Mexico

Status: Completed


La Union recently constructed a community water system, which is managed by the La Union Mutual Domestic Water and Sewer Works Association. Water services are currently provided to approximately 180 customers. The water supply is drawn from a single 400 gallon per
minute (gpm) groundwater well located approximately 1.5 miles west of the center of the community.

La Union, however, does not have a community wastewater system. Residents and businesses use on-site systems for wastewater treatment, which include septic tanks, cesspools, and, in some cases, direct discharge on or slightly below the ground surface. Many of these on-site systems are not properly sized or constructed. These unsafe methods
pose an immediate threat to public health and the risk of groundwater contamination is great due to the shallow groundwater table.


This project consists of the design and construction of a wastewater collection and conveyance system. The wastewater flows from La Union will be treated at the West Mesa/Santa Teresa Border Regional Wastewater Treatment Plant, approximately nine miles away from the collection system. A second phase of the project includes a future expansion of the existing treatment plant.

The collection system will consist of about 42,000 linear feet of gravity sewer lines, a lift station, and about 4,200 linear feet of force main sewer lines. The conveyance system will consist of about 45,000 linear feet of 6-inch force main sewer lines and four lift stations to transport the wastewater from the La Union collection system to the West Mesa/Santa
Teresa treatment plant.

The existing treatment plant currently features three parallel trains of Sequencing Batch Reactors (SBR) that allow Doña Ana County to process flows ranging between 15,000 and 300,000 gallons per day (gpd). It is estimated that by the year 2004, the treatment plant will need to be expanded to increase its capacity to 450,000 gpd to continue to accommodate the flows from La Union. This will involve among other things the installment of a fourth parallel train of SBR treatment with a 150,000 gpd capacity.


This project will provide residents with first-time wastewater collection and treatment services thereby significantly reducing public health and safety risks.

Project Financing

Total Project Cost US 7.6M
NADBank Funding US 4.24M - NADBank Grant: BEIF
Other Funding Partners Border Environment Infrastructure Fund (BEIF)
Border Environment Cooperation Commission (BECC)
Project Development Assistance Program (PDAP)
New Mexico Environment Department (NMED) - Revolving Fund Program
Remaining Costs through sewer and conveyance risks