How to allow player to be 'under water'?

Phaser 3
1

So I’ve got this tile layer in my JSON file from Tiled called ‘water’. I’m trying to create a part of the level where my character must go into the water. How would I do that without actually colliding my character with the water tiles so I can detect when I need to change the physics to slow gravity a little bit?

2

See setTileIndexCallback() etc. in http://labs.phaser.io/edit.html?src=src/game%20objects/tilemap/collision/tile%20callbacks.js.