The acreage in the top two fire zone tiers that must be in compliance with stiffer fire-safe building codes increased 76% in areas of Southern California protected by local firefighters, new state hazard maps released Monday show.

The number in the highest tier, the “very high fire hazard severity zone,” increased by 26% in the region, meaning that more residents will have to remove flammable plants and materials around their homes and will have to have properties inspected before a sale.

The maps are part of a 40-year-old program in which Cal Fire periodically documents areas that are most prone to having a wildfire within the next Wildfires