Defensible space is the buffer an owner keeps between a structure and the vegetation around it. Public Resources Code §4291 sets the rules for the structures it covers, such as a house in a state responsibility area.

Distance: defensible space is maintained 100 feet from each side and from the front and rear of the structure, but not beyond the property line unless another law, ordinance, rule or regulation requires it. Work on adjacent land can happen only with that landowner's written consent. Example: if the rear property line is 60 feet behind the house, the rear requirement stops at 60 feet.

Insurers: an insurer may require more than the standard 100 feet only if a fire expert designated by the director provides findings that the fuel modification is necessary to significantly reduce the risk of ignition, and no other feasible mitigation measure is possible. Even then, the distance may not go beyond the property line unless allowed by law. Underwriting guidelines alone do not meet this test.

Ember-resistant zone: §4291 calls for an ember-resistant zone within 5 feet of the structure. It takes effect for new structures once the Board of Forestry updates its regulations and guidance document, and for existing structures three years after that date. Existing structures must meet the same standard, but the regulations let them stage the work. For this purpose, a structure includes any attached deck.