A drilling system, comprising: a wash pipe; a housing rotatably disposed about the wash pipe; an annular space positioned between the wash pipe and the housing; a seal assembly disposed in the annular space; a seal monitoring device for monitoring the seal assembly, wherein the seal monitoring device is coupled to the housing; characterised in that the seal monitoring device comprises: a body having a central axis, a first end, a second end opposite the first end, and a through-passage extending axially from the first end to the second end; a piston slidably disposed in the through-passage of the body; a biasing member axially disposed between the body and the piston, wherein the biasing member is configured to bias the piston axially towards the first end of the body; and a signaling assembly coupled to the second end of the body, wherein the signaling assembly includes an indicator and a switch electrically coupled to the indicator, wherein the switch includes a battery and an electrical contact electrically coupled to the indicator; wherein the switch has a first position with the battery engaging the electrical contact and a second position with the battery disengaged from the electrical contact; wherein the indicator is in an activated state with the switch in the first position, and the indicator is in a deactivated state with the switch in the second position; wherein the piston is configured to translate axially in the through-passage to transition the switch between the first position and the second position; wherein the through-passage is exposed to a fluid pressure in the annular space between the wash pipe and the housing. a wash pipe; a housing rotatably disposed about the wash pipe; an annular space positioned between the wash pipe and the housing; a seal assembly disposed in the annular space; a seal monitoring device for monitoring the seal assembly, wherein the seal monitoring device is coupled to the housing; characterised in that the seal monitoring device comprises: a body having a central axis, a first end, a second end opposite the first end, and a through-passage extending axially from the first end to the second end; a piston slidably disposed in the through-passage of the body; a biasing member axially disposed between the body and the piston, wherein the biasing member is configured to bias the piston axially towards the first end of the body; and a signaling assembly coupled to the second end of the body, wherein the signaling assembly includes an indicator and a switch electrically coupled to the indicator, wherein the switch includes a battery and an electrical contact electrically coupled to the indicator; a body having a central axis, a first end, a second end opposite the first end, and a through-passage extending axially from the first end to the second end; a piston slidably disposed in the through-passage of the body; a biasing member axially disposed between the body and the piston, wherein the biasing member is configured to bias the piston axially towards the first end of the body; and a signaling assembly coupled to the second end of the body, wherein the signaling assembly includes an indicator and a switch electrically coupled to the indicator, wherein the switch includes a battery and an electrical contact electrically coupled to the indicator; wherein the switch has a first position with the battery engaging the electrical contact and a second position with the battery disengaged from the electrical contact; wherein the indicator is in an activated state with the switch in the first position, and the indicator is in a deactivated state with the switch in the second position; wherein the piston is configured to translate axially in the through-passage to transition the switch between the first position and the second position; wherein the through-passage is exposed to a fluid pressure in the annular space between the wash pipe and the housing.