This is a simple low cost waterproof DIY housing for my 2 GH13's. It's not for underwater only ON water, will take splashes etc.
I use this shooting from a Jetski/boat on the ocean etc.

It allows use of the 14 - 140 kit lens with ND to protect lens glass, the waterproof sleeve expands to full zoom and protects quite well. The controls are electrical cable glands and controls Focus/Exposure lock (one push sets focus and locks it, the others are record, power and LCD/EVF switch. These controls are all i need, camera runs shutter priority 1/100 and auto ISO. Allows more protection than say a Kata soft camera cover.

In the process of putting smaller button controls like the LCD/EVF one.

Total costs Under $50