Management system, detection device, estimation device and sewer cover

A management system is provided with a detection device (30) and an estimation device, and the detection device (30) is provided with: a main body (31) having a shape that can be provided to a discharge port; an electrode (54) as a detection unit, which is provided in the main body (31), and which detects the liquid; and a communication device (53) that functions as a transmission unit that transmits information relating to the result of detection by the detection unit, the estimation device being provided with: a reception unit that receives information transmitted from the transmission unit; and an estimation unit that estimates the discharge state of the liquid discharged from the discharge port on the basis of the information received by the reception unit. 管理系统具备探测装置(30)和估计装置，上述探测装置(30)具备：主体(31)，其具有能够设置于排出口的形状；作为探测部的电极(54)，其设置于主体(31)，探测液体；通信装置(53)，其作为发送与探测部的探测结果相关的信息的发送部发挥作用，上述估计装置具备：接收部，其接收从发送部发送的信息；估计部，其基于由接收部接收到的信息，估计液体从排出口排出的排出状态。