Sounds normal to me. Our cats are outdoor and wet fed and it used to worry me that I never saw them drink despite leaving water down for them. However, that changed when the weather was so awful during the winter as I presume their usual source (neighbour has a pond with a little fountain, suspect that's the main one) had frozen over. They still didn't drink much but I did see it happen. Once the cold snap was over they stopped drinking from their bowl again. I have also seen them drinking if I have had to keep them in for a few days. I appreciate Ianthi's point re catching things from dirty water but not sure there is much I can do to change their habits.

Before offering water to your cat make sure it's fresh, change regularly and cleans water-bowl every day. As you said, it may be possible that your cat access to the outsides. If your cat eats wet food, he doesn't need to drink really. But, if you see any abnormal behavior take advice of the vet.

__________________
"A house is not a home without a pet."