A slow kitchen sink commonly has grease, fine food debris, and soap buildup in the strainer, trap, or horizontal drain. Unlike a bathroom sink, kitchen use makes grease and dishwasher discharge especially important clues.
Start with the strainer and disposal if present
Remove visible debris and make sure the strainer is not coated with grease. If there is a garbage disposal, disconnect its power before inspection and never put your hand into the grinding chamber.
Grease often narrows the drain gradually
Fats and oils cling to pipe walls and trap particles, so a sink can go from normal to slow over weeks. Keep grease out of the drain and remove accessible buildup mechanically where practical.
Watch what happens when the dishwasher drains
If the sink gurgles or the water level rises while the dishwasher pumps out, the shared kitchen branch may be restricted. That clue points beyond a simple clogged sink strainer.
Repeated slowdowns call for a broader drain check
If cleaning the trap and accessible area helps only for a few days, grease may be farther along the line or drainage slope may be poor. A plumber can assess and clear the branch without relying on repeated chemical treatments.