[Bleufiend]

At op I love chess

The electric water pump that failed is on the bottom passenger side of the vehicle. If you want to see it and the work performed you'll have to take your splash shield off from under the engine.

Those two faults listed above in that diagnostic printout would not of been caused by a oil service, plain and simple. Karma unfortunately chose you to have your car break down right after an oil service. Also tap water or for that matter any water added to your cars cooling system is not going to damage/corrode/eat away at the system. Also that electric water pump really is just that. An electric motor with an impeller mounter in the housing that the dme speeds up or down dependent upon the cooling needs of the engine, that's it.