Fire season: defensible space requirements and your insurance

Defensible space is the ground around a house managed so that a wildfire loses intensity before it reaches the walls, and so that firefighters have room to work. In the Mountain West it is also a condition of insurability. A house surrounded by dry brush, low limbs and stacked firewood in the Prescott forest, the foothills above Boise, the canyons east of Salt Lake City or the hills around Reno and Lake Tahoe can struggle to find a carrier at renewal even if it has never had a claim.

The word requirements covers three different sources, and they rarely say exactly the same thing. This article separates them, explains the zone model that most of them share, describes how the work is inspected and documented, and sets out what defensible space does and does not change in a home policy.

Who sets the requirements

The first source is local government. Some counties, cities and fire districts in wildfire-prone parts of Arizona, Nevada, Utah and Idaho adopt a wildland-urban interface code, often based on the International Wildland-Urban Interface Code, which can require vegetation management around structures, ignition-resistant building materials for new construction and access for fire engines. Where no such code has been adopted, clearing is a recommendation rather than an obligation. The local fire marshal or county planning office can say which applies to a parcel.

The second source is private: homeowners association covenants in many foothill and mountain subdivisions set vegetation and building standards, and communities recognised under the Firewise USA programme commit to ongoing mitigation. The third, and the one that most directly affects insurance, is the carrier's underwriting guidelines. A carrier can require clearing as a condition of writing or renewing a policy even where no law requires it.

The state forestry agencies, the Arizona Department of Forestry and Fire Management, the Nevada Division of Forestry, the Utah Division of Forestry, Fire and State Lands and the Idaho Department of Lands, publish guidance and run assistance programmes, and they are a good place to confirm current standards for an area.

How the zones work

Nearly every standard divides the ground around a house into zones, measured outward from the walls, decks and attached structures.

• The immediate zone, the first few feet around the house and under decks: noncombustible surfaces such as gravel or pavers, no mulch, no plants against the siding, nothing stored under the deck, gutters and roof cleared of needles and leaves.
• The intermediate zone beyond it: grass kept short and green or cleared, shrubs spaced so they do not form a continuous path of fuel, tree limbs pruned up from the ground and away from the roof, and firewood and propane tanks moved out to its edge or beyond.
• The extended zone out to the property line or further on large lots: dead trees and fallen material removed, dense stands thinned so crowns do not touch, and ladder fuels that let ground fire climb into trees cut back.
• The house itself: ember-resistant vents with fine metal mesh, boxed eaves, a Class A roof, and double-paned or tempered windows. Many standards treat hardening the structure as part of defensible space, because embers, not the flame front, ignite a large share of homes.

What the season does, and what an inspection looks for

Grass cures in late spring and early summer, and after that each week of heat and wind raises the fire danger until the autumn rains. Clearing is best done before the grass cures, both because the work itself can start a fire in dry conditions and because inspectors from carriers and fire districts do most of their visits in spring and summer.

A carrier's inspector, or a third-party firm working for the carrier, typically photographs the house from each side, notes vegetation touching or overhanging the structure, combustible material in the immediate zone, roof covering and debris, vents, decks and the distance to neighbouring fuel. The report may carry a list of required corrections with a deadline, and failing to complete them can lead to a non-renewal. Ask for the report in writing so the work can be matched to it.

Suppose an inspection of a house outside Flagstaff notes pine needles on the roof, juniper against the north wall and firewood under the deck, and gives the owner a deadline. A landscaper quotes $2,500 for the work, and the owner completes and photographs it. The carrier renews. Had the owner ignored the report and received a non-renewal, a replacement policy in the non-admitted market might have cost, for example, $1,500 a year more, with narrower coverage. The figures are hypothetical.

What defensible space changes in the policy

Defensible space does not change what the policy covers. Fire is a covered peril on standard homeowners forms whether or not the brush was cleared. What clearing changes is whether the carrier offers or renews the policy, the premium tier the address falls into, and, with some carriers in some states, whether a mitigation or Firewise community discount applies.

Two exceptions deserve attention. A policy issued or renewed on the condition that specific mitigation be completed can give the carrier grounds to dispute a claim if the condition was not met. And the cost of clearing itself is maintenance the homeowner pays; the policy does not reimburse it. After a fire, the policy's additional coverages, such as debris removal, the fire department service charge where local departments bill for response, and a limited allowance for trees and shrubs, respond up to their own limits.

Liability when fire leaves your property

A fire that starts on a property and spreads to neighbours can bring a liability claim if the owner was negligent: burning debris on a windy day, a spark from a mower in dry grass, an unmaintained tree falling on a power line. The personal liability coverage on a homeowners policy generally responds to property damage the insured causes accidentally, up to its limit, and pays for the defence. Fire suppression costs billed by a government agency can be claimed as well, and whether and how a policy pays them depends on its wording.

Suppose a Utah homeowner's brush pile burn escapes and destroys a neighbour's barn and fencing valued at $150,000. With liability coverage of $300,000, the policy defends and pays the claim. If the fire had spread to several homes, the total could pass that limit, which is the case for an umbrella policy in wildfire country. These numbers are hypothetical.

Before, during and after fire season

The work follows the calendar.

• Before: complete clearing in spring, photograph the immediate and intermediate zones from fixed points with dates, keep landscaper invoices, and check local burn restrictions before burning any debris.
• Before: update the home inventory and confirm the dwelling limit against a current rebuild estimate.
• During: keep the immediate zone clear of new debris, move patio furniture cushions and doormats inside on red flag days, and follow evacuation orders promptly. Keep receipts for evacuation costs.
• After a fire nearby: photograph smoke and ash damage before cleaning, report the claim, and ask how smoke cleaning, debris removal and landscaping are treated.
• After the season: send the carrier documentation of any inspection corrections, and plan the next spring's work while the lessons are fresh.

The decision points

Four questions frame the season. Which requirement applies to the property: a local code, an HOA covenant, the carrier's guidelines or all three? Has the work in the immediate zone been done and photographed? Is there an open inspection report with corrections still due? And are the liability limit and dwelling limit high enough for a fire in a crowded interface neighbourhood?

If the work is done and the policy renewed without conditions, the recommendation is to keep the policy and keep photographing. If a non-renewal notice or an inspection report has arrived, send it to us. We explain what the carrier is asking for, compare the policy across the carriers we represent in Arizona, Nevada, Utah and Idaho, and tell you whether mitigation or a move to another carrier makes more sense. The analysis costs nothing.