I would agree with Geoff's summary. The Medical air plant room will have a compressor, possibly more than one and a large receiver that irons out any fluctuations in the air pressure to keep it constant. There is a drain on the receiver, which should automatically drain out any water and other contaminants. Further down the pipeline there should be dryers which will remove any residual water from the air. It sounds like these dryers have failed, and that the cartridges have not been replaced. This would be a job that your estates department or a contractor would normally do.
In the UK, the HTM document specifies that quarterly QC testing is required on Medical air plant to look for any oil based contamination, but mainly for moisture content. This again should be being carried out by the estates or a contractor. In addition to this there ought to be built in monitors for moisture content that will alert estates staff that there are issues. If there has genuinely been water contamination as far as the ventilator itself, the whole pipeline will need drying out and should not be used for patient connected equipment. The first thing to do is to sort out why there is water in there, then put purges on all outlets if possible, and get the terminal units tested until the moisture content is within the recommended -46 C dew point.
