There are a number of stormwater and wastewater requirements with any new build. A wastewater management system must be provided for each specific lot. It is a Regional Council requirement to help control the flow and runoff of wastewater from a property to the public wastewater network, to help prevent local rivers and streams flooding and reduce erosion.

This management system will include a dual purpose retention and detention raintank, required for re-use of a % of the wastewater on the property:

• Detention wastewater management - an underground structure designed to hold wastewater collected from a roof through downpipes and/or drives, paths or patios through cesspits / drains. It then manages the flow and runoff of this waste water from a property to the public wastewater infrastructure.
  
• Retention - this relates to the amount of wastewater permanently held within the dentition tank at any point in time i.e. the amount it of water it retains. Re-use of this 'grey water' for things like watering the garden, washing the car or flushing the toilets etc has become common practise in a number of subdivisions within the wider Auckland region. 
  
• All impervious surfaces such as driveways or hardstand areas require stormwater mitigation, devices such as permeable paving, raingardens, treepits can be used as management devices, it is important that all stormwater runoff is directed to these devices.
• Timber slatted decks are not considered impervious surfaces, therefore no stormwater mitigation is required when using slatted decks. Slatted decks are preferred over concrete or tiled patio areas as these would require stormwater mitigation to be provided.
  
• It is the property owner / purchaser responsibility to maintain their stormwater management devises / systems.