17 people /4 families went camping Thurs 06/19, separate campers, our family did NOT eat with the other 3, nor eat any same food except for one night: smores. We did not all swim. Starting Fri night, puking every 20 minutes and diarreah(no blood) before or after and pain below belly button-nothing else. Last one seems to have come down with the symptoms Tues night-EVERYONE but 2 adults(so far) had it What was it?

That is best left for people smarter and better paid than us. It could have been anything from a food borne illness, to blood borne that was transferred via mosquitoes, to a air borne illness. It is really hard to say, but the people should be taken care of and the doctor/hospital will figure out what the cause is.

Well we all assumed stomach flu so no one went to the dr. We were just arguing if it was food poisoning (which I don't see how since we didn't eat anything together or even cook on the same surface) or a virus (which is what I think it was because I could see how it could spread among us: Several people using same bathroom in camper, older child takes 7 yr old to park(holding hands), 7 yr old and 4 yr old playing with common toy, 4 yr old sleeping with grandpa, grandpa made the smores to hand out to the people that had smores, everyone goes to bed with their respective others... like that)

WATER in common - drinking, doing dishes, and/or cooking.

These mysteries don't always get identified, of course. I wouldn't bother with doctors now.
Happened to me once at Christmas. I spent two days sleeping on the floor outside the bathroom. Then everyone else got it 2 days after I left. Nice clean house. Who knows.
There are known lag times for each bacterial infection that affects the gut (that fall under 'food poisoning'), so you might be able to find a chart for that.

OOH didn't think of water! We didn't drink it or cook with it BUT we did wash dishes with it and wash our hands OOOOOH BRUSH OUR TEETH! Didn't think of that, thanks for mentioning that!

I hope you notify the health dept of the town (if it was campground water out of a spigot).
A weak, elderly person or infant could be affected much more than all of you were.
And just to be on the safe side, I would ask for a test report.
(If you all brushed your teeth with pond/lake/river water, then don't bother - it's your own fault.)

We reported it to the campground, they said they have had no other reports and then someone called me back later and we talked about it a little and she said they still hadn't had any calls. I guess that isn't going to be helpful if the owners aren't honest... But we don't know that it was the campground water, we haven't been able to pinpoint anything, just rule out a few things.

You really need to contact the Health Dept for everyone's sake. They aren't going to assume it was the campground water, but campgrounds are required to have water tested periodically, and to keep latrines away from water supplies, and so on, so please call them.
(Unless they are all related to each other and in cahoots... but all you can do is make that one effort.)

Water makes a lot of sense.

From the time I was little we went camping in the mountains, one particular town, same campsite every year, beach across the street.

One year I spent 90% of my time in the lake. Gorgeous lake, clear as the sky. But people pee in it, poo in it, vomit in it, and you name it.

Suddenly I got sick. It felt like the stomach flu. It got so bad that during our camping trip, we went to the hospital. It was because of the water. While I was swimming, diving, I swallowed some of the water, and that made me sick.

Same thing in Mexico in 2001. I didn't drink the water, I knew better. But I did brush my teeth with the tap water in the hotel. I figured that was fine, since I wasn't going to swallow it, I was going to wet my toothbrush, rinse, and spit it out.

Didn't matter. I was sick as a dog, and to boot, I had just found out I was pregnant with my second child 2 days before we left for the trip. I literally counted down the minutes until I could be in my own bed, puking in my own bathroom.

Contaminated water can be deadly.

Called Health Dept. I would feel horrible if someone else less healthy than us got it. I kind of worry because they had heavy rains there several times the week prior and the river (its for tubing on but it was closed because it was too high/too dangerous) is really high.. not sure if that could have any effect on their water supply or not but...
Thanks for all the replies everyone!!

In addition to the possibility of a water contaminate, it's possible that it was due to a gastrointestinal virus, which will often spread quite easily, but be relatively short lived.