Keep Cooking Oil and Grease Out of the Sink: Six Practical Steps
Grease can build up inside drains. Let used oil cool, collect it separately and follow local disposal or recycling rules.
Washing cooking oil away with hot water can still lead to grease buildup in pipes. New York City's sanitation guidance says not to pour oils, fats or grease down any drain. Local recycling rules differ, so use your municipality's collection instructions.