Watch where the water pauses. If it hangs in the basin and then trickles, something has narrowed the pipe, and in a single sink that something is usually within reach: a mat of hair under the stopper, a ring of grease inside the tailpiece, a trap choked with sludge. When two or three fixtures lag together, the narrowing sits deeper in the house. Backups and blocked lines in general are covered on our clogged drain and toilet plumber page.
What builds up in a bathroom sink drain?
Hair, toothpaste, soap and skin oil knit into a gray, rubbery plug clinging to the stopper and the pipe wall under it. Water has to squeeze past, so the basin drains in a sluggish swirl. Lift the stopper out and wipe it, and speed often returns within a minute.
Still slow? Then the film has moved lower, into the curved trap or the horizontal pipe that enters the wall. Set a bucket below, back off both slip nuts by hand, and let the trap's contents fall out. Rinse every piece, check the washers, and thread it back finger-tight plus a small extra turn.
A plastic barbed strip, pushed down the opening and pulled out slowly, grabs the hair further along. Step-by-step photos live in clearing a bathroom sink.
Why does the kitchen sink drain slowly?
Cooking fat is the culprit. It leaves the pan as a liquid, cools in the pipe, and plasters the wall, and then rice, coffee grounds and pasta stick to the coating until the opening is pencil-thin. A garbage disposal chops scraps small but does nothing about grease on the pipe wall.
Run the hot tap with a little dish soap added, for about a minute, to loosen a thin film. If only one half of a double sink lags, the clog is probably in that half's tailpiece or at the junction where the two sides meet. Take that trap off and scrub it above a bucket.
Grinder trouble gets its own treatment under disposal repair, plunger and snake technique appears in freeing a kitchen sink, and a dishwasher feeding the same trap can add to the problem, as dishwasher drain blockages explains.
What is safe to try before phoning anyone?
Go from gentle to firm. Clear the strainer. Run hot water. Press a cup plunger over the opening, keep water above its rim, pack a wet cloth in the overflow slot, and pump. Next, dismantle and empty the trap. A hair-catching strip handles the rest.
Baking soda followed by vinegar freshens a drain but seldom shifts a dense blockage, so do not expect much. Store-bought chemical openers deserve caution: splashes burn skin and eyes, a charge left sitting in a blocked line may attack some pipes, and whoever opens the trap next meets caustic liquid. Never combine two products.
One red flag: you empty the sink and a neighboring fixture gurgles or rises. Stop there, because the blockage is not in this sink.
What if the drain is slow but there is no blockage?
Slow does not always mean plugged. Leaves or a bird nest can choke the roof vent, and a drain starved of air behind the water glugs and creeps. A branch pipe laid with too little fall holds water. Scale can shrink the bore of an old line. Or a partial blockage can sit beyond the plunger's reach.
Cast iron and galvanized drains in postwar Torrance, Gardena and Lawndale houses can roughen inside with age, and rough walls snag debris. A plumber threads a small camera along the line and looks. Gurgling or a sewer odor alongside the slowness suggests venting or the main line, and chasing down a sewer smell indoors is the better read.
Why is the shower backing up with no visible clog?
A shower that fills while nothing looks stuck is usually draining into a branch that is half closed farther downstream. Hair in the trap beneath the floor is the common cause, yet a sluggish main sewer line shows the same symptom, especially when the washer or a flushed toilet makes the shower gurgle.
Test it: run the bathroom sink and watch the shower drain for bubbles, then flush the toilet with the shower empty. Bubbling, gurgling or rising water in the tub says the shared drain is restricted, and the remedy is a long snake or a water jet through the cleanout, not a sink plunger. The shower trap itself is handled in clearing a shower drain.
When is the neighbors' sewer or the main line involved?
Suspect the main when each drain you own is sluggish, when the lowest fixture (a tub or floor drain) backs up, or when neighbors report the same trouble. Roots in the lateral, a sag in the pipe, or an obstruction in the city's main can each be responsible.
Shut off the water-using appliances and call a plumber; flushing again only sends more water to a pipe that cannot take it. A camera inspection pins down the cause. Should the obstruction prove to be in the public main, the City of Torrance is who to contact; settle where your responsibility stops before work starts.
Pipe work at permit level goes to a contractor whose California license is on file. Building and Safety (310-618-5910) can tell you which jobs qualify. Our quote form opens a visit, and the Del Amo Plumbing home page has our full list of jobs.
Common questions
Roughly how long is the plumber at the house?
A trap cleaning or a short snake run commonly finishes inside an hour. A longer line, a camera pass or a main clog may need a couple of hours, plus time to open a cleanout. The quote lists what is covered and what would change the price.
Which points should I settle ahead of booking a drain plumber?
Whether the visit fee covers the snake or only the diagnosis. Whether a camera pass costs extra. What happens when the clog returns. Request the license number of the contractor, have the price written out, and learn who files any permit.
Does someone need to be home while the drain is worked on?
It helps. A person on site shows which sink is slow and approves any added work, and the plumber needs the cabinet cleared and sometimes the outside cleanout opened. Short jobs allow you to step out for a while if the plumber can reach you by phone.
Will a slow drain clear itself with time?
Rarely. A partial blockage collects fresh hair and grease and tightens, so a sink that lags today will likely crawl next month. Cleaning the stopper and trap early costs almost nothing. Waiting can end in a full stoppage at a bad moment, such as when guests arrive.
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