Water ingress: what the code requires, and who pays

Water ingress is water getting in through the envelope — roof, walls, windows, balconies. The source is outside and often slow, and that changes the code, the warranty, the strata rules and the claim.

Read from primary sources · Editor-reviewed · Current as at 20 September 2026

By the waterdamagequotesau.com editorial team · Published 20 September 2026 · Last reviewed 20 September 2026 · 8 min read

10 primary sources cited on this page. How we check what is on this site

“Water ingress” is the building industry’s phrase for water getting in through the envelope: the roof, the walls, the windows and doors, the balconies. It is a different problem from a burst pipe, because the source is outside and often slow, and that difference runs through everything that follows — the building code, the builder’s warranty, the strata rules and the insurance claim.

Where water gets in, and what each route means

Common routes for water ingress, and the questions each one raises.
Route	Building question	Insurance question
Roof, after storm damage	Repair the roof	Storm, `reg 19(1)(a)(xiv)`
Roof or flashing, slowly over time	Maintenance or a defect	Wear and tear, `reg 19(2)(b)`
Around windows and doors	The code’s weatherproofing requirement names these openings	Depends on cause and wording
Balcony over a room	External waterproofing to AS 4654.2 — leaking balcony	Depends on cause and wording
Surface water from a storm	Site drainage — stormwater	Storm, or flood if it left a waterbody
Ground moisture	Damp-proofing and subfloor — damp subfloor	Not a listed event

What the building code requires

NCC 2022, Volume Two, H2P2 (Weatherproofing) · NCC 2022, read 4 October 2026

“A roof and external wall (including openings around windows and doors) must prevent the penetration of water that could cause— unhealthy or dangerous conditions, or loss of amenity for occupants; and undue dampness or deterioration of building elements.”

That is the performance requirement for houses; it names roofs, external walls and the openings around windows and doors. The deemed-to-satisfy routes point to the cladding, glazing and masonry provisions and the standards they reference, and for balconies and flat roofs over rooms to external waterproofing to AS 4654.2. Water getting in through any of those is, on its face, a building that is not doing what the code requires — which is why ingress in a recent building is often a warranty question first.

When ingress is a defect

How three states treat water ingress in building work.
State	What the law says	Time
Queensland	Defective work that allows water penetration into a building is structural	Aware within 6 years 6 months; claim within 3 months
New South Wales	Waterproofing is a major element of a building; a building-code failure in waterproofing or the enclosure is a serious defect for apartments	6 years for a major defect, 2 years otherwise
Victoria	Work must be proper, workmanlike and comply with the building laws	Building action within 10 years

Residential Apartment Buildings (Compliance and Enforcement Powers) Act 2020 (NSW) s 3 · Wayback Machine copy of 18 January 2026 (live register refused the build host), read 4 October 2026

Part of the definition of a serious defect. Building element takes its meaning from the Design and Building Practitioners Act 2020 (NSW) s 6, which lists waterproofing and the building enclosure — roof systems and walls including windows and doors — as building elements.

Get the wet walls and ceilings dried

Four digits, and restoration companies advertising for your postcode call you back. Fixing the leak and drying the damage are separate jobs.

In a strata building.

NSW Government, Strata repairs and maintenance · last updated 22 June 2026, read 23 September 2026

Listed among examples of common-property repairs, which are the owners corporation’s. The page’s worked examples put plumbing in boundary walls and floors on the owners corporation and plumbing in internal walls and fixtures on the owner. It does not mention mould.

The NSW Government’s list of common-property repairs includes the roof and gutters, balconies and balcony doors, and windows. Ingress through any of those is usually the owners corporation’s to repair, and its building policy is the one that responds. The strata page covers how the policies meet.

Strata, the insurance claim and the drying

A storm that lifts tiles and lets rain in is the storm event in reg 19(1)(a)(xiv) (Insurance Contracts Regulations 2017 (Cth) reg 19(1)(a)(xiv)). Water that has been finding its way in for months through a perished seal or a corroded flashing is where the exclusion for wear and tear, rust or corrosion comes in (Insurance Contracts Regulations 2017 (Cth) reg 19(2)(b)). The evidence that separates them is a roofer’s or builder’s written cause, photographs, and the date it started. In a building under warranty, the builder may be the better route for the defect, with the insurer for the resulting damage.

Whoever pays for the fix, the wet frame and linings have to be dried before they are closed up. On the published rate card, two rooms over five days is $2,269 excluding GST; ceiling water damage covers wet ceilings.

Finding the entry point is often the hard part, because water travels inside a wall or roof before it shows. A stain under a window may come from the flashing above it; a damp patch on an internal wall may come from a gutter two metres away. Testing in stages — hosing one section of roof or wall at a time while someone watches inside — and moisture readings across the area narrow it down. Ask whoever investigates to write down what they tested and what they found, because that note is the evidence for the builder, the owners corporation or the insurer, whichever route the repair takes.

Common questions

What is water ingress?

Water getting into a building through its envelope: the roof, external walls, windows, doors or balconies. NCC 2022 H2P2 requires a roof and external wall, including openings around windows and doors, to prevent the penetration of water that could cause unhealthy conditions, loss of amenity or undue dampness.

Is water ingress a building defect?

It can be. In Queensland, defective work that allows water penetration into a building is structural defective building work. In New South Wales, waterproofing and the building enclosure are building elements under the Design and Building Practitioners Act, and a defect from non-compliance with the Building Code's performance requirements is a serious defect for apartment buildings.

Is water ingress covered by home insurance?

Rain through a storm-damaged roof is a storm event. Water that has been getting in slowly through a failed seal or flashing is where the wear and tear and gradual deterioration exclusions apply. What let the water in decides it.

Who fixes water ingress in a strata building?

In New South Wales the NSW Government lists roofs, balconies and balcony doors, windows and water damage coming from common property among the owners corporation's repairs; owners repair what is in their own lot.

How long do I have to claim against the builder?

In New South Wales a major defect carries a 6-year statutory warranty and other defects 2 years; in Queensland structural defects must be noticed within 6 years 6 months; in Victoria a building action can be brought up to 10 years after the occupancy permit.

What does water ingress damage cost to dry?

On the published rate card this site reproduces, two rooms dried over five days is $2,269 excluding GST, before the wall or ceiling repairs.

Sources cited on this page

Every figure above was read from the source it is attributed to on 20 September 2026. How we check this.