Calexico, California, USA

Water System Improvements Project for Calexico, California

Status: Completed construction


Calexico obtains its drinking water from a surface water supply, the Colorado River. The city's water treatment plant (Plant A) was initially constructed in 1949 with primary facilities consisting of clarifiers, filters and disinfection system. In 1965 the treatment plant was expanded, and Plant B consisting of another clarifier and a Greenleaf filter was added in 1968. In 1990, the Plant A clarifier was refurbished and the filter was converted to a conventional type multimedia filter.

In 1997, the State of California Department of Health Services (DHS) Office of Drinking Water identified numerous deficiencies in the treatment plant that compromise the ability to provide properly treated and disinfected drinking water. The State strongly encouraged the city to expand the plant in order to correct these deficiencies.


The purpose of this project is to rehabilitate and expand the existing water treatment and distribution system and consists of three phases:

Phase I:

  • Construction of additional filtration capacity of six million gallons per day (gpd) and additional distribution pumps at the filtration plant.
  • Rehabilitation of the Plant B Clarifier.
  • Construction of a new Plant C Clarifier.
  • Construction of new filters with 12 mgd capacity.
  • Conversion of existing Plant B Greenleaf filter tank to a backwash recovery tank.
  • Construction of three new evaporation basins.
  • Addition of new distribution system pumps, associated pumps,
    valves and piping.

Phase II:

Construction of a 24-inch diameter, 13,200 feet long distribution main.

Phase III

Construction of a six million gallon treated water storage reservoir and a satellite pump station.


This project will improve the city’s water treatment and distribution processes, thereby correcting the deficiencies found by the DHS. It will also provide capacity for added community growth through the year 2020.

Project Financing

Total Project Cost US 11.33M
NADB Funding US 6.48M - NADB Grant: BEIF
Other Funding Partners Border Environment Infrastructure Fund (BEIF)
Institutional Development Cooperation Program
Economic Development Administration (EDA)