[DrFeelGood]

If thats underneath I would imagine it is coming from the bearing at the front. I would replace it.
An Aisin WPZ045 pump is under $50 US and they are usually the Japanese OEM supplier. You could also go with PEDD-15-010A for $90 which will likely be an Aisin in a Mazda box...but maybe not.

 

[DrFeelGood]

The tensioner is what loads the bearings so I am inclined to go with OEM. Perhaps the Aisin water pump and OEM tensioner with aftermarket belt is a reasonable price compromise?
A quality aftermarket belt should be fine.

 

[DrFeelGood]

If you do run an OEM pump grab the numbers off it and see if it can be matched to an Aisin pump.