DS1 (3 in June) is recently potty trained and it's only since we've done this that I've really noticed how little he drinks. We offer him water all day but he usually takes one sip and then says he's had enough. Yesterday he only went to the loo twice! 
Should we be worried or is he drinking to thirst? I can't force him to drink and the only option I have is to offer him juice rather than water which I'm reluctant to do as I suspect he'll refuse water altogether then!
My MIL has helpfully suggested I give him tea!

So, do I need to worry or is this another stage he will just grow out of (he used to drink loads!)? 