So I've been offered a darkroom recently and I feel it would be a great place to process my sheet film and make some contact prints. The plumbing is decent with only one tiny leak. The ventilation system is functioning and the sink is a large steel one. My issues are that it has been quite damp down there for a while and unused in about a year. I have reason to believe that mold has grown but not much visual evidence except for perhaps what are some strange black spots in one of the damp but mostly little used sinks. I am not entirely sure of the water quality. What tests should I run to determine whether it is safe for archivally processing my film? It does have a basic filtration in which I just replaced the 5 micron filter. Are there any concerns as to potential mold fumes and my film drying down there? What else should I be looking for? Sorry if some these questions are a little strange, however I am curious and wonder whether I should bother sinking a little money into this free darkroom or continue to travel a longer distance to my current spot. Thanks in advance.