Water <-> Energy: Water plays a key role in energy production, for irrigation, in hydroelectric plants, for cooling thermal (fossil-fuel or nuclear) plants and in growing plants for biofuels. Conversely, energy is required to process and distribute water, power water supply equipment (solarization), pump and treat groundwater, etc.

Water <-> Housing: Water is the keystone for housing construction and repairs, housing needs, concrete and bricks production, etc. Conversely, agricultural intensification for households’ activities impacts water quality.

Housing <-> Energy: Energy is essential to life and comfort in the home. It is needed for lighting, heating, cooking, and income-generating activities. It is an input throughout the home’s construction, from pumping water to processing, transporting, and refrigerating food in the house.

Integration between water, energy, and housing is an essential requirement for the sustainability of all the above. It is negatively affected if water, energy, or housing are unsustainable within the urban planning subsystem and the integrated human settlement.