Hornsby flood map check

Hornsby Shire Council publishes its own flood mapping, and the Site Checker reads it for any Hornsby address. The checker reads its 1% AEP and probable maximum flood extents, and the flood planning map in Hornsby's local environmental plan, which is still in force on the NSW Planning Portal.

Type an address below to see what each map says about the block, with its source and date.

Check your address

NSW addresses only. Free, and no sign up.

Is my Hornsby property flood affected?

A Hornsby property is flood affected for planning when it is in the flood planning area on Hornsby's LEP flood planning map, and the council also marks flood control lots on its section 10.7 planning certificates. The Site Checker above reads the council's layers, the NSW Planning Portal map and the NSW SES extents, and shows each answer separately. The official answer is still Hornsby Shire Council's, and the questions below explain how to get it.

Where is the Hornsby Shire Council flood map?

Hornsby Shire Council publishes an interactive flood map with its flood risk management work on its Your Say flood risk management page, which covers the shire's 38 urban catchments. The LEP flood planning map is on the NSW Planning Portal spatial viewer.

Which Hornsby Shire Council flood layers does the Site Checker read?

The checker reads the two extent layers behind the council's HSC PMF Flood Mapping 2503 web map: the 1% AEP flood extent, which covers about 2.6 per cent of the shire, and the probable maximum flood extent, about 8.1 per cent. Neither layer names a study or a date, so a reading from them names none.

The checker asks 2 layers: 1% AEP flood extent and Probable maximum flood extent. Every one answered a test query on 17 September 2026. The council's flood control lot layers are left out: they are whole property outlines that also carry owners' names and postal addresses, and a query for one lot returns its neighbours too. The Hawkesbury River extents map the river flood rather than a council control.

What is a flood control lot in Hornsby?

It is a lot Hornsby Shire Council has identified as subject to flood related development controls, and the council has noted flood control lots on its section 10.7 planning certificates since 2012. The notation is a flag on the property: it tells you the council's flood controls apply to development there, and the planning certificate is where you find it.

How do I get a flood certificate from Hornsby Shire Council?

Hornsby Shire Council does not list a separate flood certificate on its website. The formal answer is the section 10.7 planning certificate, which has carried the flood control lot notation since 2012, and flood questions about a development go to the council's development engineers, whose flood risk management manual page sets out the controls.

Why does the Hornsby Shire Council map differ from the state map?

They are drawn by different bodies for different jobs. The NSW SES Flood Database compiles flood extents from studies across the state, while Hornsby Shire Council's map is the one its planning controls are written against, and a flood planning area usually sits above the 1% AEP extent because it adds freeboard. The flood planning map in Hornsby Shire Council's local environmental plan, on the NSW Planning Portal, is read as a third source. The checker never merges the sources into one verdict, and where they disagree, Hornsby Shire Council settles it.

What else do people ask?

Does the Hornsby flood map show how deep the water would get?

No. An extent says whether land is inside a modelled flood, not how deep or fast the water is. Flood levels in metres AHD (height above average sea level) come from Hornsby Shire Council, through the council's development engineers.

If my Hornsby block is outside the mapped area, can it still flood?

Yes. Hornsby's flood risk work covers 38 urban catchments, and flooding from the Hawkesbury River is mapped separately. Land outside every map can still flood from overland flow no study has modelled, and a council can apply flood controls to land its published map does not show.

Is this the same as a section 10.7 planning certificate?

No. Hornsby Shire Council's section 10.7 planning certificate is the formal statement of the controls on a lot, including whether flood related development controls apply. Order one through Hornsby Shire Council certificate requests.

Where does this information come from?

This page and the Site Checker are general information from published maps, not a flood certificate, a section 10.7 planning certificate or a survey. They do not replace advice from the council, your certifier, an engineer, a lawyer or your own designer. Check any decision to buy or build against the council's own documents.