Metropolitan's distribution system consists of 830 miles of large diameter pipelines, including approximately 400 connections to member agencies. The regional distribution system became operational in 1941, two years after completion of the Colorado River Aqueduct.
The CRA is a 242-mile system of aqueduct, tunnels and siphons. On the CRA, tunnels vary in length from 338 feet to 18.3 miles, comprising 38 percent of the aqueduct's length. Most are horseshoe shaped and are 16-feet in diameter. Metropolitan has an extensive ongoing program to refurbish and maintain the distribution system to ensure reliable water deliveries.