A method for detecting fluid consumption that includes: detecting, by a fluid meter mounted on an exterior of a pipe containing fluid, a first time of flight between a first ultrasonic transducer and a second ultrasonic transducer; detecting, by the fluid meter, a second time of flight between the second ultrasonic transducer and the first ultrasonic transducer; determining a time of flight difference between the first time of flight and the second time of flight; determining a volumetric flow rate based on an environmental correction parameter and the time of flight difference; and generating a fluid volume consumption total for fluid flowing through the pipe based on the volumetric flow rate.