bedrock-samples/behavior_pack/loot_tables/dispensers/trial_chambers/water.json

{
  "pools": [
    {
      "rolls": 1,
      "entries": [
        {
          "type": "item",
          "name": "minecraft:water_bucket",
          "weight": 1,
          "functions": [
            {
              "function": "set_count",
              "count": 1.0
            }
          ]
        }
      ]
    }
  ]
}