Wellington Water (5 Councils)

Source Documents

These are the council documents used to build the WW calculator. If a link is broken, the document may have moved on the council website.

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Managing Stormwater Runoff Version 5 (March 2024)

PDF Primary Source

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WW Stormwater Information Page

Council website - may contain updated links if documents above have moved.

Calculation Methodology

Retention

Emergency water supply in lower tank (15-25% of volume)

Method

Approved Solution #1 - Rainwater Tank. Min 80% of new roof area diverted to tank. Covers Upper Hutt, Hutt City, Porirua, Wellington City, and South Wairarapa.

Design Requirements

• Min 80% of new roof areas diverted to tank
• Overflow must NOT connect to main stormwater system
• Overflow to visible overland flow path
• Leaf litter/debris diverter required
• Tank bottom max 0.5m above ground (avoids building consent)
• Emergency water supply in lower tank

Submission