Hermosa Beach and Redondo Beach rank second and third, respectively, in a regional contest to save water and cut pollution.
Vernon is first as of Monday, according to the Wyland Foundation, which is sponsoring the competition called The Mayor's Challenge.
The contest between Southern California cities runs through the end of April in honor of Earth Month.
The Wyland Foundation will announce the winner on May 3.
Residents in the victor city will be eligible for tickets to Los Angeles Angels of Anaheim games and Disneyland as well as discounted passes to the Aquarium of the Pacific in Long Beach.
Ranking behind the top three cities are Long Beach, Villa Park, Mission Viejo, Monrovia, Torrance, Huntington Beach and Rolling Hills Estates.
Wyland Foundation Vice President Steve Creech said at this point, the standings are fluid.
"A few hundred pledges from any city could easily change the balance of the standings," said Creech.
To make a pledge, go to www.mywaterpledge.com.
