func_water

1.Firstly, create a good sized room (300x300x300) and place your info_player_start and a light in there.

2.Next add a water brush below the room.
NOTE: You may have to put the water brush in another empty room with light on its surface, or give the top face of the water brush a light value in your editor's face properties dialogue box, otherwise the water surface will be black. Apply the func_water entity to it.
Give it a

"targetname"  "water1"
"lip" "8"
"angle"  "-1"

3.Place a trigger_once brush in the room, so when the player walks across it it triggers the water. Give it a

"target"  "water1".

4.Compile your map and check it out in Quake2.