Inline pool/spa monitoring device and system including pool/spa pump operation determination and associated methods

Exemplary embodiments are directed to systems and methods for monitoring pool or spa water, and determining an operational status of a pool or spa pump. The system includes a monitoring device engaged with a component of a pool or spa plumbing system, and in communication with a server. The server receives data from the monitoring device relating to characteristics of water within the component detected by the monitoring device. Based on the received data, the server can determine whether the data should, be discarded, and a runtime of the pump. The server can also receive vibration energy information from the monitoring device, determine runtime events of the pump based thereon, and determine whether the data should be discarded based on the vibration energy information. An adapter for coupling a monitoring device to a pool or spa plumbing system component, and retaining fluid within a reservoir portion thereof is also provided.