Of the mixture, about 30% is oil, Chevron says, meaning nearly 240,000 gallons of crude have spilled out onto the earth.
Don Drysdale, a spokesman for California's Division of Oil, Gas, and Geothermal Resources, told CNN that officials had a slightly different preliminary estimate of the oil spill than Chevron did.
California says Chevron allowed "surface expressions" of oil to occur May 10, June 8 and June 23.
According to the California order, Chevron has responded to notices from regulators about the issue.
This year's inland spill in California is larger than a 2015 California oil spill that spewed 105,000 gallons of crude oil out of a ruptured pipeline off the coast near Santa Barbara.