Commercial Fixed Wing
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 12
Communication Breakdown; Distraction; Time Pressure
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
General None Reported / Taken
Environment - Non Weather Related; Human Factors
I was notified about a report of a wrong surface landing. I was the Controller on the midnight shift.  I cleared Aircraft X for Runway XXC; but the Aircraft landed Runway XXR. Approach switched the aircraft on an extended base for the visual approach [to] Runway XXC. The pilot checked on the frequency for Runway XXC. I cleared the aircraft to land for Runway XXC. After I cleared the plane to land the janitorial guy comes to the Tower cab to vacuum the Tower and empty the trash. I usually go opposite of him so we can keep our space (we had our mask on) for social distancing. When he finished cleaning the Local 3 position I recognized the aircraft was short final to Runway XXR. I knew the runway had no vehicles on it because my strip bay showed no vehicle above Runway XXR bay header. I let the aircraft land Runway XXR due to the critical phase in flight. I taxied the aircraft to the ramp after the aircraft landed safely. In the past Approach would call me on the shout line to remind me that this aircraft is set up on the wrong approach. By me not being at the position walking around the Tower cab I did not recognize the aircraft on approach for the wrong runway.The recommendations I would use to prevent this wrong surface landing is to observe an aircraft turn onto the right approach for the right runway. If that pilot makes a mistake turning on to the wrong approach I can either send the aircraft around or correct the aircraft to land on the proper runway; or I can help the pilot get visual for the runway the pilot is lined up for and clear the plane to land for that runway. The key is catching the aircraft turning on the approach early enough so I can correct the pilot.
ATC Tower Controller reported an aircraft landed on the wrong runway and cited social distancing distraction during a janitorial service in the Tower as a contributing factor.