What grease does inside a pipe
Bacon fat, butter, cooking oil, gravy, salad dressing and even the thin film on a dinner plate all contain fats. Warm, they pour easily. As they move through the drain, they cool against the pipe wall and harden. Each rinse adds a layer. Food particles and soap get trapped in it, and the pipe slowly narrows from the outside in. Eventually a big rinse after a holiday meal finds the gap too small, and the sink stops.
Running hot water doesn't solve it. It carries the grease a little further before it cools, which just moves the clog deeper into the line, where it's harder and more expensive to reach.
Where garbage disposals fit in
A disposal grinds food into small pieces so it can travel through the drain. It doesn't remove grease, and some foods cause trouble on their own: fibrous peels and celery wrap around blades and catch in pipes, while rice, pasta and potato peels swell into a paste. Coffee grounds and eggshells settle in low spots. Used with plenty of cold water for soft food scraps, a disposal is fine. Used as a trash can, it adds to kitchen clogs.
Kitchen habits that prevent clogs
- Pour cooled grease into a can or jar and throw it away
- Wipe pans and plates with a paper towel before washing
- Use a sink strainer and empty it into the trash
- Run cold water while the disposal runs, then let it run a little longer
- Keep peels, rice, pasta, coffee grounds and eggshells out of the disposal
Early warning signs
- The sink drains slower than it used to
- Gurgling when the dishwasher pumps out
- Water rising on one side of a double sink when the other drains
- A sour smell from the drain
Clearing a grease clog
A plumber usually starts with a cable through the trap arm or a cleanout. That opens a path, but a grease-coated pipe narrows again quickly. If the line has clogged before, hydro jetting is worth considering: it scours the walls clean rather than just punching a hole through the middle. In older homes with cast iron or galvanized kitchen lines, jetting can make a dramatic difference.
Holiday season
Thanksgiving through New Year's is the busiest season for kitchen clogs. Big meals mean more grease, more dishes and more disposal use, often with guests who don't know the house's habits. A quick reminder in the kitchen and a jar for grease by the stove prevent a lot of holiday calls.