One always like to stay into the water in hot summer. Some parents may have not time to take their children to some public locations like pool, sea beach and others during summer vacations. Did you ever think of to play in your yard/house?
I got Balloons Kits, a toy in fact, for kids outdoor play. It is very easy to use and, mostly important, very safe. No need to worry about getting hurt.
Quick fill water balloons: Self tying water balloons Fill & Tie 111 water balloons in less than 60 Seconds!
If you like it, you could find it here: http://bit.ly/2t2bgCI
Wish you a good time!