*6.2. Semi-Centralized Infrastructure*

The smart water grid is a semi-centralized system and relies on both decentralized and centralized infrastructure to provide diverse sources of non-potable water. A pre-existing dual reticulation system is required as part of the envisioned system to circulate non-potable water that is generated at lower water quality for end uses such as irrigation and flushing toilets. Constructing a secondary pipe network within an existing water supply system is typically cost-prohibitive, and implementation of the smart water grid may be better incorporated into new systems, such as the network that is conceptualized for Fisherman's Bend near Melbourne, Australia [59]. A smart water grid for micro-trading rainwater could also be implemented using a shared aquifer [49] or water trucks to provide conveyance of traded water. Micro-trading rainwater can also use a water rights structure, where households buy the rights to use rainwater from a community source. Rainwater harvesting provides a sustainable source of water by recycling runoff; however, rainwater is an unreliable source, and it is likely that rainwater would be unavailable at times when irrigation water is needed most, such as during droughts. By taking a semi-decentralized approach that incorporates rainwater tanks into a reclaimed water network, diverse sources are utilized to meet potable demands. Diverse portfolios of water sources can lead to reliable water supply systems [96], and the smart water grid would meet demands during low rainfall by circulating reclaimed water and reusing rainwater when it is available. Other benefits of decentralized water management associated with a smart water grid may include offsetting household energy costs [97] and reducing stormwater flows [37].
