Grass Flat flood map & planning overlays
Grass Flat's 80 ha lots are Horsham's 2nd-biggest.
Free map preview, then PDF reports from $9 - about the price of an iced latte on a public holiday.
A planning-constraint profile of Grass Flat
(Horsham, VIC) - 69.72 km², mapped from live council and
state overlay data. This suburb is highly constrained.
Profile updated 24 October 2026.
Constraint readout
69.72 km² - this suburb is highly constrained by planning overlays.
Elevation hillshade with street names, clipped to Grass Flat's boundary, with the flood, bushfire and environmental overlays drawn on top.
Nearby suburbs, nearest first
Aircraft noise and flight paths over Grass Flat
The ANEF contour is a published planning forecast and observed overflight is what a sampled tracking feed recorded - neither describes any individual property.
Observed overflight - sampled to
Night movements: not established - night is sampled as often as day, but too few night flights have been seen here to conclude either way.
How this is measured
Traffic is sampled rather than watched continuously, so every figure is a floor: aircraft not captured between samples are not represented. Rates are per 500 m square - the busiest square in the suburb, not a count of flights over the suburb - and a square is only rated where enough traffic was seen to measure it. Altitudes are above mean sea level. Flight paths change with runway use, weather, season and airspace design. This is a record of observed traffic; it is not a noise contour and not a planning control.
Grass Flat at a glance
How Grass Flat is zoned
Selling in Grass Flat? The zoning and planning overlays on this page are the controls a Section 32 vendor statement discloses.
Across its 69.72 km², Grass Flat is highly constrained by planning overlays. About 3% of the suburb sits within a mapped flood overlay, and 100% is flagged bushfire-prone. The dominant land-use zone is Farming Zone (FZ). The median lot measures about 804,641 m² across 76 parcels.
Who lives in Grass Flat
Census 2021 figures published by the ABS for the Grass Flat suburb boundary itself, not a wider region.
Socio-economic standing
ABS SEIFA 2021 ranks every Australian suburb. Decile 1 is the most disadvantaged tenth of the country, decile 10 the least.
Score 1014, and decile 6 within Victoria. The national average is 1000.
Age profile
Share of Grass Flat's 47 residents in each ABS age band.
Population trend, 2001 to 2025
Estimated resident population of Horsham Surrounds, the wider ABS statistical area containing Grass Flat. There is no annual population series published at suburb level, so this describes the surrounding area rather than Grass Flat itself.
3,565 in 2001 to 3,399 in 2025, down 5%.
Source: ABS Census 2021 and SEIFA 2021 (Suburbs and Localities), Regional Population (SA2), CC BY 4.0. Small counts are randomly adjusted by the ABS.
Grass Flat data sources and coverage
“Not mapped” means we hold no source layer for this suburb - never an all-clear.
| Dataset | Coverage | Publisher |
|---|---|---|
| Flood mapping | Mapped | Vicmap Planning and Victorian Government spatial services |
| Bushfire-prone mapping | Mapped | Vicmap Planning and Victorian Government spatial services |
| Zoning | Mapped | Vicmap Planning and Victorian Government spatial services |
| Heritage and environment | Mapped where published | Vicmap Planning and Victorian Government spatial services |
| Aircraft noise contours (ANEF) | Not held | Vicmap Planning and Victorian Government spatial services, Defence |
| Observed flight paths | Observed | adsb.lol, under the Open Database License |
| Demographics | Available | Australian Bureau of Statistics (2021 Census and SEIFA) |
Profile last materially updated 24 October 2026. See the methodology and full source list. Source data changes over time and critical decisions should be checked with the responsible authority.
Check a specific Grass Flat address
See exactly which overlays touch a single property - the interactive map is free. Need it on paper? A full planning PDF is just $9.
See what's in the $9 report →Building or pricing a slab? The $119 geotechnical desktop report covers geology, soils, bores and the indicative soil reactivity range to expect for a Grass Flat lot.
Grass Flat planning - frequently asked
Is Grass Flat flood-prone?
About 3% of Grass Flat falls within a mapped flood overlay, against the council-wide suburb average of 16%.
Is Grass Flat bushfire-prone?
Around 100% of Grass Flat is mapped as bushfire-prone, compared with a Horsham average of 98%.
Is Grass Flat under a flight path?
No aircraft were observed over Grass Flat in the period sampled (recent weeks to now). Sampling is intermittent, so that is a floor rather than proof that none fly over. Traffic is sampled rather than watched continuously and flight paths change with runway use, weather and season; the ANEF contour is the planning instrument.
What is the zoning in Grass Flat?
The dominant planning zone in Grass Flat is Farming Zone (FZ), though the suburb also includes Farming Zone (FZ1) and Public Conservation and Resource Zone (PCRZ).
Does Grass Flat have heritage-listed places?
No heritage-listed places are on record within Grass Flat.
What is the typical lot size in Grass Flat?
Across 76 surveyed parcels in Grass Flat, the median lot size is about 804,641 m². There are also 29 registered easements mapped in the suburb.
Is Grass Flat an advantaged suburb?
On the ABS SEIFA 2021 index of relative socio-economic advantage and disadvantage (IRSAD), Grass Flat scores 1014 and sits in decile 7 of 10 nationally and decile 6 within Victoria (decile 1 is the most disadvantaged tenth, decile 10 the least).
Compare nearby suburbs
| Nearby suburb | Distance | Flood mapped | Bushfire-prone |
|---|---|---|---|
| Mitre | 7.2 km | 20% | 96% |
| Duchembegarra | 8.5 km | 14% | 95% |
| Arapiles | 9.8 km | <1% | 100% |
| Natimuk | 13.0 km | 13% | 100% |
| Nurcoung West Wimmera |
15.1 km | 2% | 100% |
| Tooan | 18.1 km | 16% | 100% |
| Little Desert Hindmarsh |
20.2 km | 2% | 100% |
| Gymbowen West Wimmera |
21.5 km | 8% | 100% |
| Quantong | 22.4 km | 18% | 100% |
| Noradjuha | 22.4 km | 16% | 100% |