Just recently attended grandson's birthday party there. Seven years old is pretty much the perfect age for there, I think. Really, most of the water is not very deep. It did seem to be clean, but it was VERY crowded. My daughter had been promised a party room and did not get one---oops, we overbooked was their excuse. Have since learned from others that is a common occurance there. (She did receive compensation, though.)
If you are staying at the hotel, you could probably hit the water park a little earlier/later and it would not be so crowded. I thought the number of lifeguards was more than adequate. They did close down one section while we were there because someone had been sick in the water. The chlorine smell was evident, but not overwhelming, so I'm guessing the water was monitored well.
If you go, there is a Kohl's and a Costco right there should you need to take a break, or the entrance to I-84 is right there--you could go to the mall in town (not great) or the Carousel Museum in Bristol. Hartford and New Haven are fairly close, too. Hartford would be the easier of the two to get to on the highway. HTH.
Forgot to add there is a game room upstairs, too.