A water meter system to be installed in-line with a fluid conduit comprising: a flow tube having a hollow internal space to receive and conduct fluid flow; a controller having a processor; a sensor installation comprising: a flow sensor for sensing fluid flow in the conduit; and a vibration sensor to detect vibrations in the upstream fluid conduit and transmit vibration data to the controller, characterised in that the controller is configured to use a sensed characteristic of the fluid flow from the flow sensor in conjunction with the vibration data to identify a leak condition of the fluid conduit; wherein the vibration sensor comprises: a piezoelectric transducer; and a base connected to a seismic weight and in abutment with the flow tube for receiving vibrations propagated from the fluid conduit, wherein the base, seismic weight and piezoelectric transducer are axially aligned, and wherein the water meter system further comprises upstream and downstream coupling portions to couple the water meter system to the fluid conduit and a spring that acts to bias the seismic weight onto the piezoelectric transducer. a flow tube having a hollow internal space to receive and conduct fluid flow; a controller having a processor; a sensor installation comprising: a flow sensor for sensing fluid flow in the conduit; and a vibration sensor to detect vibrations in the upstream fluid conduit and transmit vibration data to the controller, characterised in that the controller is configured to use a sensed characteristic of the fluid flow from the flow sensor in conjunction with the vibration data to identify a leak condition of the fluid conduit; wherein the vibration sensor comprises: a piezoelectric transducer; and a base connected to a seismic weight and in abutment with the flow tube for receiving vibrations propagated from the fluid conduit, wherein the base, seismic weight and piezoelectric transducer are axially aligned, and wherein the water meter system further comprises upstream and downstream coupling portions to couple the water meter system to the fluid conduit and a spring that acts to bias the seismic weight onto the piezoelectric transducer. a flow sensor for sensing fluid flow in the conduit; and a vibration sensor to detect vibrations in the upstream fluid conduit and transmit vibration data to the controller, characterised in that the controller is configured to use a sensed characteristic of the fluid flow from the flow sensor in conjunction with the vibration data to identify a leak condition of the fluid conduit; wherein the vibration sensor comprises: a piezoelectric transducer; and a base connected to a seismic weight and in abutment with the flow tube for receiving vibrations propagated from the fluid conduit, wherein the base, seismic weight and piezoelectric transducer are axially aligned, and a piezoelectric transducer; and a base connected to a seismic weight and in abutment with the flow tube for receiving vibrations propagated from the fluid conduit, wherein the base, seismic weight and piezoelectric transducer are axially aligned, and wherein the water meter system further comprises upstream and downstream coupling portions to couple the water meter system to the fluid conduit and a spring that acts to bias the seismic weight onto the piezoelectric transducer.