Spray a 6 - 7 quart slow cooker with non-stick spray. Place potatoes in slow cooker then pour water evenly over top**. Toss with salt and pepper then add garlic and pour butter evenly over potatoes and garlic. Cover and cook on high heat 4 - 4 1/2 hours until potatoes are tender when pierced with a fork . Mash potatoes with a potato masher then add sour cream, heavy cream. Whip with an electric hand mixer until desired texture is reached, while adding in milk to reach desired consistency. Serve warm with more butter if desired and minced chives.
