Answer

Water fountains are located across the University of Sunderland campus for members of the University to use free of charge. The University Student's Union also maintains a list here: https://www.sunderlandsu.co.uk/campaigns/freewater 

Here are the locations of the water fountains please see links to the building opening hours - most faculty buildings close by 7pm the University Library has longer opening hours as does City Space

City Campus

Fleming corridor ground floor
Fleming corridor 1st floor
Fleming corridor 2nd floor
Pasteur corridor ground floor
Pasteur corridor 1st floor
Johnson ground floor
Johnson 1st floor
Priestman – Dance corridor 
Murray Library ground floor
City Space

St Peter's Campus

Reg Vardy: Water fountain next to Men’s toilets on every floor.
David Goldman: Water fountain next to ground floor toilets.
Media Centre: No water fountain. Taps are single taps, one cold / one hot. Disabled tap is a mixer.
Prospect Building: In St Peter's Library, drinking fountain outside toilets.

The University Estates and Facilities team oversee the installation and maintenance of water fountains. If you have further questions or comments about water fountains please contact Estates and Facilities by calling 0191 515 3366 or emailing estatesandfacilities.helpdesk@sunderland.ac.uk