I refuse to carry anything.  Just hate doing it.  Thus, all of my long runs involve stops for water at a bare minimum.  I stash bottles and stop to drink.  I have never checked the time but I probably stop for a minute or so.  I did a 20 mile run yesterday and between stopping to drink and stopping to cross the road a couple of times, I was stopped for a total of 7 minutes but I ran for 2:35.  Importantly, I put in 12 x 1 minute accelerations with 1 minute jogs after Mile 15 but I made sure when I was on the quality portion that I was on part of the route where I wouldn't need to stop.  In looking at several of my previous long runs, I'm typically stopped anywhere from 3-7 minutes out of the 2:00-2:30 that I'm running.

I figure that as long as I don't a) stop during a quality portion of the run or b) let my heart rate drop under 100 b.p.m., then the stopping is irrelevant.

I got into the habit when I first started doing runs over an hour of eating Cliff shots before I got to the county regional park, then getting water at the park and using their indoor facilities. Every time. Even if I didn't really need the water, shots or pee break. I think this year, I have only used the park facilities once. But it is nice to know there are indoor facilities on my route. 

I don't really put much attention to that because the necessary stops I have during a normal run (I cannot evade lights down here and I don't have trails to run consecutively) never happen in the race.  My guess is that any breaks (being so short even though cumulatively large) will not affect too much to be a concern.