Every subdivision consent in New Zealand comes with engineering conditions. The specifics vary by council, but the categories are consistent: stormwater management, flood hazard, erosion and sediment control, and three waters connections. This post compares the conditions you will typically see from Auckland Council, Wellington City Council, and Hamilton City Council, so you know what to expect before you lodge.
These are not hypothetical. They are drawn from consent decisions issued in the last three years. If you are developing in any of these jurisdictions, your consent will almost certainly include some variation of every item below.
Stormwater neutrality and detention
Auckland Council
Auckland's stormwater neutrality requirement is anchored to TP108. The standard condition requires post-development peak flows to not exceed pre-development flows for the 2-year, 10-year, and 100-year ARI events. Pre-development is typically defined as the existing land cover at the time of application, though Auckland Council sometimes requires assessment against a pasture baseline for greenfield sites.
Detention sizing must account for climate change rainfall uplift using HIRDS v4 data. Auckland currently applies a 16.4% increase to the 100-year, 2-hour rainfall depth under RCP 8.5 at 2081 to 2100. You will see this written into conditions as a requirement to design for "mid-range climate change scenario" or referenced directly to the Auckland Council climate change technical guidance.
Wellington City Council
Wellington's stormwater conditions are governed by the Wellington Water regional standard. Hydraulic neutrality is required for all developments that increase impervious area. The standard condition requires detention to limit post-development discharge to pre-development rates for the 10-year and 100-year ARI events. Wellington Water's preference is for on-site detention with a controlled outlet, and they generally require an operations and maintenance plan as a condition of consent.
Wellington conditions frequently include a requirement for water quality treatment in addition to flow attenuation. The typical requirement is treatment of the "first flush" volume, defined as the first 25 mm of rainfall over impervious surfaces, using a proprietary device, rain garden, or constructed wetland.
Hamilton City Council
Hamilton's stormwater management is administered under the Waikato Regional Council's stormwater framework, with Hamilton City Council imposing site-specific conditions at subdivision consent. Stormwater neutrality is required for all new development. Hamilton conditions typically reference the Waikato Stormwater Management Guideline and require detention to limit post-development discharge to 80% of the pre-development 2-year ARI peak flow for water quality purposes, and 100% of the pre-development peak for the 10-year and 100-year events.
The 80% reduction for the 2-year event is a distinctive Hamilton/Waikato requirement intended to provide extended detention for water quality treatment. This means Hamilton detention volumes are typically larger than an equivalent Auckland site.
Minimum floor levels and flood hazard
Auckland Council
Where a site is within or adjacent to a flood-prone area, Auckland conditions require minimum floor levels set at the 100-year ARI flood level plus 500 mm freeboard. If the site is affected by an overland flow path (OLFP1 or OLFP2), the condition will specify building setbacks and may require the flow path to be maintained at a specific cross-section and gradient. The Auckland Unitary Plan (AUP) E36 provisions govern flood hazard and often generate conditions requiring a site-specific flood hazard assessment where the regional flood mapping shows potential risk.
Wellington City Council
Wellington flood conditions typically require minimum floor levels at the 100-year ARI flood level plus 500 mm freeboard for habitable rooms and 300 mm for garages and non-habitable structures. Wellington's topography means many sites have steep overland flow paths with high velocities. Conditions commonly require overland flow paths to be identified, protected from obstruction, and designed to convey the 100-year ARI flow without increasing flood risk to neighbouring properties.
Hamilton City Council
Hamilton sits on the Waikato River floodplain and has extensive flood hazard mapping. Minimum floor level conditions reference the Hamilton City District Plan and require habitable floor levels at the 100-year ARI flood level plus 500 mm freeboard. Hamilton conditions may also require specific foundation types (e.g. raised timber floor rather than slab-on-grade) in areas with shallow flood depths to allow underfloor conveyance during extreme events.
Erosion and sediment control
Auckland Council
Auckland's erosion and sediment control (ESC) requirements are the most prescriptive in the country. Conditions reference Auckland Council's GD05 (Erosion and Sediment Control Guide for Land Disturbing Activities). For earthworks exceeding 2,500 m2, a certified ESC plan is required, and the ESC devices must be installed and inspected before bulk earthworks commence. Conditions routinely require chemical treatment (flocculation) of sediment-laden water using polyaluminium chloride (PAC) or similar, particularly on clay soils.
Auckland conditions also require a nominated ESC site manager who holds an Auckland Council-recognised ESC training qualification. Monitoring and reporting obligations are typically weekly during active earthworks and within 24 hours of any rainfall event exceeding 25 mm in 24 hours.
Wellington City Council
Wellington ESC conditions reference the Greater Wellington Regional Council's Erosion and Sediment Control Guidelines. The requirements are broadly similar to Auckland's GD05 but less prescriptive on chemical treatment. Wellington's steep terrain means ESC conditions place particular emphasis on stabilisation timeframes, with conditions typically requiring exposed earth to be stabilised within 14 days of completion of works in any area, or sooner if heavy rainfall is forecast.
Hamilton City Council
Hamilton ESC conditions reference the Waikato Regional Council's Erosion and Sediment Control Guidelines for Soil Disturbing Activities. The Waikato approach is broadly aligned with Auckland's GD05 but adapted for the Waikato's alluvial soils. Conditions typically require sediment retention efficiency of 95% for particles greater than 0.035 mm. Chemical treatment is required where suspended sediment levels in discharge cannot meet the receiving water standards without it.
Three waters connections
Auckland Council (Watercare)
In Auckland, three waters connections are managed by Watercare. Consent conditions require the developer to obtain a Watercare connection approval before construction. Conditions specify pipe materials (typically PE100 SDR17 for water and PVC-U for wastewater), minimum pipe grades, and connection details. Watercare requires as-built plans to be submitted in a specific digital format (GIS-compatible) before the connection is accepted for vesting.
A common Auckland condition is the requirement for a wastewater capacity assessment where the development connects to an existing network with known capacity constraints. This can add weeks to the engineering programme if Watercare identifies the need for network upgrades.
Wellington City Council (Wellington Water)
Wellington Water manages the three waters network. Conditions require compliance with the Wellington Water Regional Standard for Water Services. A distinctive Wellington requirement is the seismic resilience condition: new water mains and laterals in identified earthquake-prone zones must use flexible PE pipe and mechanical couplings at specified intervals. Wastewater conditions frequently require CCTV inspection of new mains and laterals before vesting.
Hamilton City Council
Hamilton manages its own three waters network under the Hamilton City Infrastructure Technical Specifications (HCITS). Conditions require water supply design to provide a minimum residual pressure of 300 kPa at the point of supply and a minimum fire-fighting flow of 25 L/s for residential zones. Wastewater conditions require gravity connections where feasible and restrict pump stations to situations where gravity connection is physically impossible. Hamilton conditions also require a minimum 48-hour pressure test on all new water mains before connection to the live network.
Conditions unique to each council
Auckland: comprehensive stormwater consent
For larger developments, Auckland Council may require a comprehensive stormwater consent (CSC) in addition to the subdivision consent. The CSC covers the long-term management of stormwater from the development and typically requires the creation of a stormwater management plan, a maintenance schedule, and a legal mechanism (consent notice or encumbrance) to ensure ongoing compliance. This is a separate consent process with its own processing timeframes.
Wellington: wind assessment
Wellington conditions sometimes include a wind assessment requirement for multi-storey developments, particularly in the central city and exposed hillside locations. While not strictly a stormwater condition, it affects site layout and can influence the location and design of stormwater infrastructure where roof areas and catchment boundaries change as a result of the wind assessment.
Hamilton: comprehensive stormwater discharge consent
Waikato Regional Council requires a comprehensive stormwater discharge consent for developments discharging to the Waikato River or its tributaries. This is separate from the Hamilton City Council subdivision consent and includes conditions relating to contaminant loads, particularly zinc and copper from roofing materials. Conditions may restrict roofing materials or require treatment devices to achieve specified dissolved metal concentrations in discharge.
What to do before you lodge
- Request a pre-application meeting with the council's engineering team. They will tell you which conditions are likely and whether any site-specific issues will generate additional requirements.
- Commission your geotechnical and topographical surveys early. Most stormwater conditions require design calculations that depend on ground levels and soil infiltration rates.
- Engage your civil engineer before finalising the lot layout. Stormwater detention, overland flow paths, and three waters connections all influence where lots can be located and how infrastructure is routed.
- Budget for ESC compliance. In Auckland particularly, ESC implementation and monitoring can represent 5% to 10% of the earthworks contract value.
- Allow programme time for Watercare/Wellington Water approvals. These run in parallel with but are separate from the council consent process, and delays in connection approval can hold up construction.
Auckland, Wellington, and Hamilton all require stormwater neutrality, minimum floor levels in flood-prone areas, erosion and sediment control, and compliant three waters connections. The differences are in the detail: Auckland's TP108 and GD05 requirements are the most prescriptive, Wellington adds seismic resilience and water quality treatment, and Hamilton's 80% reduction on the 2-year ARI event means larger detention volumes. Knowing which conditions apply to your council before you start the engineering design avoids redesign and programme delays.