Source Documents
These are the council documents used to build the NPDC calculator. If a link is broken, the document may have moved on the council website.
Land Development and Subdivision Infrastructure Standard (Local Amendments v3)
Calculation Methodology
Design event: 10-year (10% AEP)
Method: On-Site Disposal Required
New Plymouth's primary requirement is on-site disposal. Soakpits, swales, basins, or rainwater tanks are the preferred approach. Connection to the council stormwater network is only permitted where no on-site option is available.
New Plymouth, Stratford, and South Taranaki share the Taranaki Land Development standard.
Design Requirements
- On-site disposal is the primary requirement
- Soakpits, swales, basins, or rainwater tanks
- Connection to council network only as last resort
- Shared Taranaki standard with Stratford + South Taranaki
Submission
Required Documents
- Site-specific stormwater design
- Soakage test results
- Engineering plans
- Resource consent (if applicable)
Contact
Last verified: April 2026 · NZ Detention Tank Calculator