Australian standards and Code requirements we work to, with the source for each.
The Code requires downpipes to sit as close as practical to where valley gutters discharge. On roofs with several valleys feeding one length of gutter, a downpipe in the wrong position overloads that section long before the rest of the run fills.
The National Construction Code allows a single downpipe to serve no more than 12 metres of eaves gutter. Long unbroken runs on Sydney terraces and wide Federation frontages often sit over that limit, which is why they overflow in heavy rain even when the gutter is clean.
Observatory Hill has averaged around 1,213 mm of rain a year on records kept since 1858. A 150 square metre roof therefore sends roughly 180,000 litres a year through its gutters and downpipes, which is why a blockage shows up as overflow so quickly.
Last updated: 8 October 2026
Roofing work in the Inner West has its own rules: heritage areas and tight access all change how the job is done. Everything below links to the council or standard it comes from, so you can check it yourself.
The whole suburb is a conservation area, recognised as Australia first planned garden suburb, with a period of significance from about 1900 to the 1940s. In practice almost every roof job in Haberfield is a heritage job.
Source: Inner West Council, C54 Haberfield HCAThe DCP limits replacement roofing to unglazed terracotta Marseilles tiles, terracotta shingle tiles, Welsh slate, or non-reflective corrugated galvanised steel, and the steel only at the rear or on skillion roofs. Finials and ridge capping have to be kept and reinstated.
Source: Inner West DCP 2016, Chapter E2, controls C17-C21Haberfield does not permit skylights on the front or side of the main roof and does not permit dormers at all. Hot water and solar tanks cannot sit on the roof either: they go inside the roof space or out of public view.
Source: Inner West DCP 2016, Chapter E2, controls C11-C15 and C89The Marrickville Valley flood study found 3,989 properties taking more than 150mm of water in a 1 per cent storm, and 3,151 properties still flooded to that depth in a storm as common as a 2 year event. Flat ground and slow drainage are the cause, so undersized downpipes and blocked gutters bite in ordinary rain.
Source: Inner West Council, Marrickville Valley Flood StudyIn the Dobroyd and Hawthorne Canal catchments, 885 of 1,446 and 690 of 1,036 flood planning lots are affected by overland flow alone. Where your roof water is discharged, and whether it is piped properly to the kerb, matters more than how close you are to a watercourse.
Source: Inner West Council, Dobroyd and Hawthorne Canal FRMSP 2020We cover Haberfield, Ashfield, Summer Hill, Croydon, Leichhardt, Annandale, Balmain, Rozelle, Lilyfield, Marrickville, Dulwich Hill, Petersham, Stanmore, Newtown, Enmore, St Peters, Tempe, Sydenham and Lewisham.
In the Inner West it depends on whether the house sits in a heritage conservation area such as Haberfield or Annandale. Haberfield is a conservation area from end to end, and its DCP limits replacement roofing to unglazed terracotta Marseilles tiles, terracotta shingle tiles, Welsh slate or non-reflective corrugated galvanised steel, the steel only at the rear or on skillion roofs.
In Haberfield only at the rear: the Inner West DCP does not permit skylights on the front or side of the main roof there, and does not permit dormers at all. Hot water and solar tanks cannot sit on a Haberfield roof either.
Inner West gutters overflow easily because much of the area is flat and drains slowly, so even ordinary storms flood homes. The Marrickville Valley flood study found 3,151 properties taking more than 150mm of water in a storm as common as a 2 year event, and in the Dobroyd and Hawthorne Canal catchments most flood-affected lots are hit by overland flow alone.
Over $5,000 your roofer needs a licence and a written contract. The deposit is capped at 10%, and over $20,000 you must see the…
Read the guideHaberfield is a conservation area from end to end. Four permitted roofing materials, no dormers, skylights off the street side, and asbestos in almost…
Read the guideCouncil flood studies show the Inner West floods in common storms, not just rare ones, and that overland flow does the damage. What that…
Read the guide