BAL-LOW: the lowest Bushfire Attack Level
BAL-LOW is the lowest of the six Bushfire Attack Levels. A site gets it when there's too little vegetation near the building, or the vegetation is far enough away, that the risk doesn't warrant bushfire construction requirements. It means very low risk, not no risk: embers can still travel a long way.
What puts a site at BAL-LOW
Under Method 1, a site is BAL-LOW when no classifiable vegetation is close enough to give a higher level. That usually means one of these: the nearest bush is more than 100 metres from the building, the only vegetation nearby is the kind the standard lets an assessor leave out (such as small or narrow patches, or managed gardens and lawns), or the building sits in a built-up area with no bush within range.
What it means for building
AS 3959 sets no bushfire construction requirements for BAL-LOW. Your state's rules still apply, so check with your building surveyor.
In Victoria, the rule changed on 1 May 2026. Before then, every new home in a designated bushfire prone area had to be built to at least BAL-12.5, even if the site was assessed as BAL-LOW. That requirement (Regulation 157 of the Building Regulations 2018) has been removed, so a BAL-LOW site in Victoria no longer has to meet BAL-12.5. You'll still see the old rule on older council and industry pages.
Should you build above BAL-LOW anyway?
Many owners choose some ember protection even at BAL-LOW, because embers start most house fires during bushfires and they can travel well beyond 100 metres. Screened vents, sealed gaps and gutter guards are cheap to add during a build and hard to retrofit later.
Can a BAL-LOW site change?
Yes. A BAL belongs to a building in a particular place. If bush regrows or is planted near the building, or a neighbouring block stops being managed, the level can go up. Moving the building closer to vegetation can too. See BAL-12.5 for the next level up.
How to lower your BAL explains how distance and slope change a site's level, and the BAL calculator by state covers each state's rules.
BAL Buddy gives an indicative Bushfire Attack Level (BAL) only. It isn't a determination under any Act, and no council or building surveyor has to accept it. For a BAL you can rely on, use an accredited bushfire practitioner.
Questions people ask
Does BAL-LOW mean there's no bushfire risk?
No. It means the risk from the vegetation near the building is very low. Embers can still reach the house, which is why some owners add basic ember protection anyway.
Do I need a BAL assessment if I think my site is BAL-LOW?
If your land is in a mapped bushfire-prone area, your building surveyor will usually want a formal assessment to confirm it. An indicative result is a good way to find out whether that's likely before you pay for one.
Is BAL-LOW the same as not being in a bushfire-prone area?
No. Bushfire-prone mapping says whether bushfire building rules apply to the land. BAL-LOW is a site-specific result, and you can get it inside a mapped bushfire-prone area.
Do I still have to build to BAL-12.5 in Victoria?
Not since 1 May 2026, when Regulation 157 was removed. A site assessed as BAL-LOW no longer has to meet BAL-12.5.