NCC 2022 Housing Provisions Part 7.4
Design rainfall 201 mm/h at 5% AEP · 262 mm/h at 1% AEP (Table 7.4.3d).
Plan area of roof draining to this one downpipe (tables cover up to 70 m²).
Eaves gutter length this downpipe drains — max 12 m.
Continuous overflow measuresper metre of gutter
Dedicated overflow measuresper downpipe
Enter the roof catchment area to draw the overflow gauge.
Enter the dimensions above to evaluate compliance.