Green roofs and stormwater
Recent extreme rainfall events across New Zealand have highlighted the growing importance of effective stormwater management in urban areas, where existing infrastructure is increasingly under pressure. One of the key benefits of green roofs is their ability to significantly reduce and slow stormwater runoff, and many councils are now recognising this value by streamlining resource consent processes.
Can green roofs help you get consent for development?
Yes they can but it will differ from council to council.
How green roofs help with stormwater (and consent).
- Reduce peak runoff (they slow water down during heavy rain)
- Retain rainfall (Up to 80% of total annual rain water doesn’t enter stormwater infrastructure)
- Delay discharge into council stormwater systems
- Improve water quality (filtering sediments + nutrients)
Because of this, councils often see them as a mitigation measure.
Where this helps most with resource consent
Well designed green roofs can support consent where:
- Impervious surface limits are tight
- On-site stormwater attenuation/management is required
- Downstream flooding is a known issue
- Low Impact Design (LID / WSUD) is encouraged
- You’re trying to avoid or reduce the size of detention tanks
Additional benefits of green roofs
The Sempergreen Click ’n Go system uses pre-grown sedum trays that offer nearly full plant cover on installation — they help absorb and retain rainfall immediately once established.
A green roof doesn’t just look beautiful—:
- sustainable,
- low-maintenance,
- encourages biodiversity
- and brings life back to forgotten spaces.
To find out more – see or contact Will directly.
Will Thorne
Managing Director, Greenroofs Ltd & Sempergreen New Zealand
[email protected]
02040195022
Greenroofs design and install unique living roofs across New Zealand. Choose from lightweight, low-maintenance sedums or full intensive roof gardens featuring NZ natives, tussocks, and grasses. We create custom solutions for every green roof.