Methods, systems, and apparatus, including computer programs encoded on computer storage media for utility monitoring and utility usage determination, control and optimization. The system receives utility usage information from one or more sensor devices, and obtains water usage information from a first sensor device coupled to a water pipe, obtains electricity usage information from a second sensor device coupled to an electrical panel, and/or obtains water heater usage information from a third sensor device coupled to a water heater. The system may use the obtained utility information to determine types of utility activities and/or appliances being used corresponding to the utility usage.