I change my budgie's water everyday but I never see him drink from it. I thought that it's because he's doing it when I'm not looking, but I'm usually around all day, so if that's the case he's REALLY holding out. Also, he'll eat in front of me, so I don't see why he wouldn't drink in front of me. Especially considering I heard you mention once that birds get dehydrated easily, I'm quite worried about him! What can I do to make him want to drink?
If he’s still alive and well he’s probably drinking, a bird would not be doing so well after about 2 days without water! They really don’t drink all that often, I usually only see my guys drink around 2-4 times a day (4 is really unusual) so there is a strong chance that he’s drinking, you’re just not seeing it. They get a lot of fluids from fresh fruits and veggies along with sprouted seeds so visiting the water dish doesn’t need to happen too frequently. If you see him defecate and notice the brown or green stool, white urates and the clear fluid urine then he’s definitely drinking, if he wasn’t there’d be little to no urine and potentially increased urates. If you pinch the skin a dehydrated bird’s skin will take more than a second to return to it’s normal state, the skin around the eyes may also appear over-wrinkled, and the bird will generally be lacking energy.
How to get birds more interested in water
Other ways to get more fluids would be to feed more watery foods like fruits and lettuces, frozen foods, soaked seeds, and things like that.