The relationship between household water use and energy consumption was examined to establish whether the conservation of water within a domestic environment offers significant potential for saving energy, thereby reducing household carbon dioxide emissions.  Average UK water usage is 55,121 L ca^-1yr^-1. The supply of this volume of water and its subsequent treatment by the water companies is equivalent to just 38.6 kg CO₂ ca^-1 yr^-1, although this is not currently included in the primary footprint. So water consumption per se does not significantly effect CO₂ emissions.  However, the heating water within the household using electricity requires 5,036 kWh ca^-1yr^-1, equivalent to a further 2,830 t CO₂ ca^-1yr^-1 with 57% of energy associated with use of heated tap water. Using gas instead of electricity to heat water can reduce emissions by 63%, equivalent to an average reduction of 4.36 t CO₂ yr^-1 for a standard household (2.4 occupants). Water efficient appliances and the careful use of heated water in the home could reduce average household water use from 151 to 73 L ca^-1d^-1 as well as the volume of water required to be heated thereby reducing related emissions by 58% or 1,662 kg CO₂ ca^-1yr^-1, where electricity is used. Maximum CO₂ emission reduction is achieved by the use of solar collectors using gas as standby heating fuel. This, coupled with simple water conservation measures, emits as little as 130 kg CO₂ ca^-1yr^-1 a potential saving of 2.7 t CO₂ ca^-1yr^-1.