Why Does My Drain Keep Clogging?

Kitchen drain clogs are most commonly caused by grease, fat, and cooking oil that solidify on pipe walls over time. Each time you pour grease down the drain — even with hot water — some of it sticks. Over months and years, the buildup narrows the pipe until clogs become frequent. The fix is hydro jetting, which blasts the pipe walls clean with high-pressure water. Snaking cuts through the clog but leaves the buildup on the walls, which is why the clog returns quickly.

Tree and shrub roots are drawn to the moisture and nutrients in sewer lines. They enter through joints, cracks, and small defects in the pipe, then grow inside the pipe, catching debris and eventually causing complete blockages. Root intrusion is extremely common in older homes with clay or cast iron sewer lines. Snaking temporarily clears the roots, but they regrow quickly. The permanent solution is either root treatment chemicals (for minor intrusion), pipe lining, or pipe replacement depending on the extent of damage.

Older sewer pipes — particularly clay tile and cast iron — can crack, shift, or partially collapse over time. A damaged pipe creates a low spot where debris accumulates, or a rough interior surface that catches material. No amount of snaking fixes a damaged pipe. A sewer camera inspection is the only way to see what's actually happening inside the pipe and determine whether repair or replacement is needed.

Drain pipes require a specific slope (typically 1/4 inch per foot) to allow waste to flow by gravity. If a pipe was installed with too little slope, waste moves too slowly and settles. If the slope is too steep, water runs ahead of solids, leaving them behind. Either condition causes chronic clogs. This is a structural issue that requires pipe replacement to correct.

Drain pipes need air venting to flow properly. A blocked or improperly installed vent causes negative pressure in the drain system, slowing flow and causing gurgling sounds, slow drains, and clogs. Vent blockages are often caused by debris, bird nests, or ice in cold weather. A plumber can diagnose venting issues and clear or repair the vent stack.