AHH! How do I get Sadie to stop hitting?

Sadie used to just hit me to go outside if she needed to potty. Now, she hits me to wake me up in the morning or even earlier in the night to fill up her water bowl. She hits me for attention. I think she even hits me just to hit me.

This is *very* painful. I have red marks on my back from her attempts to wake me up (which work). I've tried to ignore her to show her that it doesn't work, but eventually, I have to get up-my back can't take it anymore. It hurts! She hits my legs if I'm standing or sitting for attention. Since I'm in shorts a lot (in Texas), this is painful as well. She does this to my roommates, too. They've tried a harsh "No", which sometimes works (for me, too, but especially out of two guys who have much deeper voices than me), but she just does it again later. I want to stop the behavior entirely.

Any ideas? Squirt guns don't work, though Riley picked up the hitting behavior and a water bottle works for him-thank goodness, b/c he really hurts... but again, he still tries the behavior again later. I don't pet them for it. I'll get up and move, ignore them as best I can-except for getting up, like I said, and even then, I try not to do what they want-go outside, fresh water-immediately, so they don't think it's a rewarding behavior.

Help!

I haven't tried that, so I should give it a go. Sadie is usually *very* easy to train, which part of why I can't figure this out. I assume that I am responding often enough to make the behavior beneficial to her, but I'm not sure how to not respond (I can't not get up in the morning, b/c it hurts like heck-I have to move away). She's a very smart dog, and that just makes her behavior even more frustrating.

Chester did that too....and still occasionally 'forgets' .  We just grab his paw and hold it...and refuse to let go.  He is NOT happy without that paw, so it's a rare occurance, now, thank heavens!!!