How can I tell if the wate pump is bad or the.

Check the engine oil first. Often these noises can be caused by bad engine bearings (crankshaft bearings).

If the water pump is causing this noise you should be able to grasp its pulley and shake if from left to right and up and down. If you can, replace it.
Timing belt tensioner is a little more difficult. You'll have to see it in operation and to do this you'll need to remove the front timing belt cover. So check the engine oil and water pump and then we'll tackle the timing belt tensioner. (Just for the record they rarely make that much noise)

As stated, do those checks first. I believe you have a lower engine issue from your description.

Roy