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Zone 0 in California, Oregon, Firewise, and IBHS
Zone 0 is the first five feet. California is writing a statewide rule. Oregon publishes guidance. Firewise USA recognizes communities. IBHS scores a parcel. They are not the same document. R327 is none of them.
You are standing with your heel on the siding, looking out five feet. Bark, a wood fence, a doormat, and stored fuel sit in the band embers actually reach. The figure on this page is the band language. It is not in-force California law as of 23 August 2026.
Why it matters
People hear “Zone 0 is law” and rip out every plant the week of a Board vote. As of 23 August 2026, California’s rule was voted and not yet filed. Oregon still does not put Zone 0 in R327.
How the four documents differ
| California Zone 0 (AB 3074 line) | Oregon OSFM | Firewise USA | IBHS Essential | |
|---|---|---|---|---|
| Kind | Defensible-space regulation, once effective | Public guidance | Community recognition | Parcel designation |
| In force 23 Aug 2026? | No. Board voted 19 Aug 2026. OAL review still expected | Guidance, not a building permit | Voluntary annual site status | If you apply for the designation |
| First five feet | Reduce combustibles. Phased for existing homes. Immediate for new construction after the effective date | River rock, gravel, or pavers. Remove bark mulch | Not a Zone 0 specification | Noncombustible zone. No wood or rubber mulch |
| Binds every lot? | No. SRA and VHFHSZ in LRA, once effective. Locals may adopt alternatives with similar effect | No | No | No |
Board staff memos from August 2026 said new construction would comply on the effective date, existing homes over about five years, education first. Confirm the Secretary of State filing before you treat a California lot as bound.
The paths
1. California lot in mapped high hazard. Watch the OAL filing. Do not wait to remove bark and stored fuel. IBHS and CAL FIRE already want that. See home-hardening ladder.
2. Oregon lot. OSFM five-foot buffer is guidance. R327, where adopted, does not inspect your mulch. You can still fail IBHS.
3. Firewise site. Recognition is not a planting list. See Firewise USA.
4. IBHS applicant. Essential Zone 0 is in the technical standard. Bark mulch fails it.
Do not scrape Discovery West landscape exhibits.
What people mix up
- Treating the 19 August vote as in-force law the next morning.
- Pasting California Zone 0 onto an Oregon R327 drawing.
- Planting the fire-resistant-rated plants in the first five feet.
- Calling Firewise a Zone 0 spec.
How to check
Name the document you are scoring. If it is California regulation, check whether it has been filed. If it is OSFM, it is guidance. If it is IBHS, download the current technical standard. If it is Firewise, look up the site’s standing.
Limits
This page will go stale when OAL files the rule. The date on the page is the verification. It does not decide a local ordinance that already exceeds the state draft.
Related records
Landscaping, plants, fence as a wick, zone bands.
Sources
Questions
Is California Zone 0 in force on every CA lot today?
No. The Board of Forestry voted on 19 August 2026. Staff expected Office of Administrative Law review and a possible effective date in September 2026. New construction would have to comply once the rule is effective. Existing homes would phase in over five years. This page does not treat the vote as a lot-by-lot mandate until the regulation is filed.
Does Oregon have Zone 0 in R327?
No. R327 is a construction section. Oregon’s State Fire Marshal publishes defensible-space guidance that names a five-foot buffer with river rock, gravel, or pavers. That is not R327.
Is Firewise USA a Zone 0 spec?
No. Firewise USA is community recognition. IBHS Essential is a parcel designation that requires a 0–5 foot noncombustible zone. Do not mix the three.
Can I plant the fire-resistant-rated plants in Zone 0?
No. Zone 0 is never a planting palette on this site.