Mr. Davis and others have argued that, at least when it is public agencies fighting the fires, it is an unfair use of resources and that as wildfire season in California worsens, the state should reconsider the amount of new housing that can be built in high-risk areas. (In recent years, some homeowners in fire-prone regions have begun to be dropped by their insurers.)

A new report by Los Angeles County found that emergency services were seriously unprepared to respond to last year’s Woolsey Fire, and that in a fire that size, residents cannot always expect public agencies to protect them.

When the blaze broke out, many fire crews in the state were already busy fighting the Camp Fire in Northern California and another fire in Ventura County. (Some in Malibu also reported that firefighters failed to arrive during the blaze.)

With that memory still fresh, Hidden Hills residents considered hiring a private firefighting service.

Instead, they bought their own fire engine. The pickup-size truck, which comes equipped with a water tank and hoses, is designed to fight blazes in rural areas. Local volunteers are training to use the vehicle to put out brush fires and hot spots.

“I want to make sure the next time people stay behind, we’re better equip ped and not putting anyone’s safety at risk,” Mr. Freedland said. “ Having a truck that has water and a pumper on board is a game changer.”