The plaintiffs say the "shelter has a duty to help, not harm, homeless dogs and cats."
The Animal Legal Defense Fund along with three people from Stockton filed the lawsuit against the City of Stockton.
The suit is not asking for money, only that the animal shelter follow the law.
The shelter is required to hold strays for at least 6 days before euthanization.
But Animal Legal Defense Fund Attorney Jenni James says the shelter's records show a different story over a one year period.
"Early euthansias are happening, 1,500 animals were euthanized before the expiration of the Stockton shelter's minimum holding period," says James.
James says 80 percent of the animals are behind locked doors where the public never sees them.
"Only about 20 percent of the animals are truly being given a meaningful chance of adoption," says James.
The City of Stockton is not commenting on the lawsuit.
The judge in Stockton's bankruptcy case has given final approvalfor the city to implement its restructuring plan.
Research firm RealtyTrac released November housing data today - and there were mixed results for the San Joaquin Valley.
President Obama's plan to normalize relations between the U.S. and Cuba is drawing mixed reactions. Some refugees who escaped to this country from Cuba are among the most critical.
This has been one of the worst years for water hyacinth in the Delta. A town hall meeting was held to speak to the concerns of those affected.
A new bill in the legislature proposes the first steps to locating a California State University campus in the City of Stockton.