If you're starting a new project or a major renovation, the first step is to set objectives for your home in different areas, including water.
Reflecting on the way you use water at home and how you are likely to use it in the future will help you to identify the type and scope of impacts that matter to you.
It is important to consider how your water needs may change over time. For example, the water use of couples changes when a baby arrives, when children grow into teenagers, and when the kids leave home.
The objectives that are important to you will impact the strategies, methods and systems that are used in your project. For example:
- Concerns about water bills could lead you to make changes in your behaviour and include products or features in your home that reduce water use.
- Wanting to contribute to the reduction of the citywide summer peak could result in landscaping that uses native and drought-resistant plants.
- Aiming to be as independent as possible from the city's water supply may require rainwater collection and reuse.
After defining your objectives, the next step is to quantify them as targets. This will help you to communicate what you want to other people, such as designers and suppliers of systems. Targets can guide the design process and inform decision making throughout your project, and when your home nears completion they can facilitate testing and verification. A target might look like one of the following examples:
- I want to spend no more than $500 per year on water bills.
- I would like to use 120 litres of water per day, staying below the Auckland average.
- I want 50% of the water used at home to be sourced on site.
- I want to be independent from the city water supply and only use water we collect and recycle.
You could also use a certification system/ratings tool to help quantify your objectives. These systems and tools have been tested and implemented by others in the past, and can provide a simple framework for decision making. The table below explains how water criteria are addressed in each of the tools described in these articles, as well as the objectives and targets they have set.
Certification
scheme | How
does it address water objectives? | Water
targets |
Building
Code | Focuses on bare minimums to
ensure occupants’ health. Clause G12 refers to water
supply and considerations to ensure it is safe. Clause G13 discusses foul
water and related provisions to safeguard people from illness. | Performance targets are not
set for residential buildings within the Building Code. |
Living
Building Challenge | Buildings need to achieve net
positive water which means all the building’s water needs must be supplied by
natural closed-loop water systems. All grey and blackwater needs
to be treated on site. | 100% of the project’s water needs must be supplied via rainwater or by
recycling used project water, and purified without the use of chemicals. |
Net
Zero Energy | There are no mandatory water
considerations as part of the Net Zero Energy certification. | N/A |
Homestar | Addresses water objectives in terms of reduced water consumption and
better water management. Focuses on the selection of the right technologies and efficient
fixtures and fittings to achieve reductions on water usage. The ‘Water’ category accounts for 15% of the points in the Homestar
tool. | Specific water targets are not set for Homestar. |
Passive
House | There are no water
considerations as part of the Passive House standard, only those related to
the energy used in heating water. | N/A |
High
Standard of Sustainability (HSS) | Water consumption is one of the five benchmarks set by the HSS. The target is a starting point based on national data and Beacon’s
demonstration projects, and it is meant to evolve over time. | Water consumption from the mains needs to be no more than 125 litres
per person per day for both new and existing homes. |