Site Services Explained: Water, Wastewater and Stormwater for New Developments

Site services are the systems that allow a development to connect with essential infrastructure. For most subdivision and land development projects, this includes water supply, wastewater disposal and stormwater management.

Understanding these requirements early can help determine whether the proposed development can be serviced, what engineering work may be required and whether upgrades or alternative solutions need to be considered.

What Does Site Services Design Include?

Site services design looks at how water, wastewater and stormwater will be managed across a development.

Depending on the project, this may include:

• Connecting new lots or buildings to existing networks

• Designing private drainage systems

• Confirming suitable connection locations

• Assessing whether existing infrastructure has enough capacity

• Coordinating pipes with buildings, roads and accessways

• Preparing plans for council review and construction

The required level of design will depend on the size of the development, the infrastructure already available and the conditions applying to the site.

Water, Wastewater and Stormwater Explained

Although these systems are often considered together, each serves a different purpose.

Water supply

Water supply design establishes how each lot or building will receive a reliable connection to the water network. This may involve confirming connection points, pipe routes, pressure requirements and any infrastructure upgrades.

Wastewater

Wastewater systems carry sewage and used water away from buildings. The design needs to consider the location and depth of existing pipes, available capacity and whether the proposed development can connect using gravity.

Stormwater

Stormwater design manages rainwater from roofs, paved areas and the wider site. Depending on the property, water may be directed to a public network, managed within the development or controlled through detention, retention or soakage systems.

Where flooding or overland flow paths are a concern, site services may also need to be coordinated with flood modelling.

Why Do Connection Points and Capacity Matter?

The nearest pipe is not always the most suitable connection point. Its location, depth, condition and available capacity can all affect the design.

Potential constraints may include:

• Infrastructure located outside the property

• Pipes that are too shallow or too deep

• Limited network capacity

• Easements across neighbouring land

• Existing private drainage systems

• Difficult ground levels

• Additional council requirements

These issues can influence the cost and feasibility of a development. Identifying them early gives the project team more time to review the layout or investigate alternative servicing options.

When Might Site Services Design Be Required?

Engineering input may be needed when a project involves:

• Subdividing land

• Adding multiple dwellings or buildings

• Creating new infrastructure connections

• Relocating existing drainage

• Increasing demand on public networks

• Changing site levels

• Building over or near existing services

• Meeting resource consent conditions

A simple development may only require a limited design package. Larger or more constrained projects may require detailed plans, calculations and coordination with council or network providers.

How Do Site Levels Affect Infrastructure?

Water and drainage systems need to work with the physical levels of the site.

Wastewater generally relies on gravity, so pipe depth and slope can affect where buildings are placed. Stormwater also needs a clear route away from structures, while earthworks can alter how surface water moves across the property.

Coordinating site services with earthworks design can help ensure the proposed levels and infrastructure work together before the design is finalised.

What Information Will an Engineer Need?

Useful information may include:

• The property address

• Existing survey or site plans

• The proposed development layout

• Building locations and floor levels

• Available council infrastructure records

• Resource consent conditions

• Previous drainage or engineering plans

• Details of any known servicing issues

An initial review can help establish what information is already available and whether further surveying, investigation or council input is required.

Choosing a Site Services Design Provider

A suitable provider should be able to consider the three water systems together and understand how they connect with the wider development.

Useful capabilities include:

• Reviewing existing infrastructure

• Identifying practical connection options

• Coordinating services with buildings, access and earthworks

• Preparing clear plans and calculations

• Addressing council requirements

• Updating the design as the project changes

• Supporting the project through approval and construction

A multidisciplinary consultancy like Civix can make coordination easier where engineering, surveying, planning and environmental requirements overlap.

Site Services Support From Civix

Civix provides site services design for subdivisions, land development and infrastructure projects.

The engineering team can assess water, wastewater and stormwater requirements, identify servicing constraints and prepare coordinated designs for council review and construction. Where required, Civix can also support the project through engineering approval, helping maintain continuity between the initial design and the approved civil works.