Is Water pump/alternator/belt replacement necessary?

Hello, I can't say if it's a water pump or alternator noise -- but, step one would be to remove the drive belt to see if the noise continues. If it stops, check each pulley (with the engine off) to see if you can narrow it down to a components that is binding or making noise. If the noise continues with the belt off, you know it has to be something that is not related to the accessory drive -- alternator / water pump / air conditioning compressor, tensioner and idler pulleys.