Never, never, never pour oil or cooking grease down a drain. It does not make it to the sewer. It stays in your system while clogging and eating away at your pipes. There is a device that you can install. Royal Flush, the best plumber in Snellville, GA, has got you covered. They are called grease traps and it cools down any water going down your drain and separates all grease before it heads to the sewer