Clogged Bathroom Sink? We'll Fix It Fast.

What causes a clogged bathroom sink, and how does a plumber fix it?

A clogged bathroom sink is almost always a mat of hair, toothpaste and soap scum caught on the pop-up stopper or sitting in the P-trap, and a plumber fixes it by pulling the stopper, opening or replacing the trap, and cabling the branch line if the blockage is past the wall.

Where the blockage sits decides the fix. A stopper or trap clog is cleared at the sink. A blockage in the small branch line behind the wall needs a drain cable run through the trap arm, which is still a routine drain-cleaning visit. If the trap itself is corroded chrome or a cracked plastic slip joint, we replace it rather than reassemble a part that will drip the next day.

What do we check first on a clogged bathroom sink call?

• The pop-up stopper and the tailpiece

  We pull the stopper assembly and look at the pivot-rod opening, because most bathroom sink clogs start on the stopper itself and never reach the trap.

• The P-trap and its slip joints

  We open the trap over a bucket and check the washers and the inside of the trap wall. A trap that is scaled or corroded inside stays slow no matter how often it is cleaned.

• Whether the tub or shower in the same bathroom is slow too

  If a second fixture drains slowly, the problem is in the shared branch line, so we cable from the sink trap arm instead of stopping at the trap.

• The faucet aerator and the supply stops

  A sink that fills slowly and drains slowly can be two separate problems. We check the aerator and the shut-off valves so one visit answers both.

When is a clogged bathroom sink not a drain-cleaning job?

Some bathroom-sink calls are not clogs at all. When the symptom points somewhere else, we say so and quote that work on its own page's terms instead of cabling a drain that is not blocked.

• Water under the vanity, not in the sink

  A trap arm, slip joint or supply line that drips when the sink runs is a leak, not a clog. It is repaired as pipe repair.

• Weak flow from the faucet while the drain is clear

  If the bowl never fills fast enough to overwhelm the drain, the drain is not the issue. Weak flow at one fixture usually comes from a blocked aerator, a failing supply stop or a corroded supply line, which is low water pressure.

• The toilet or the tub backs up when the sink drains

  Water moving between fixtures means the blockage is below the branch line, in the stack or the main sewer. That is a camera-first call that belongs to sewer line service.

What should I do before the visit?

1. Clear the vanity cabinet so the trap is reachable and put a towel down; we bring a bucket, but the cabinet floor is the first thing that gets wet.
2. Stop using chemical drain cleaner now. If any has gone down the sink in the last day, say so when you call so the technician can open the trap safely.
3. Note whether the tub, shower or toilet in the same bathroom is also slow; that one detail decides whether we cable the branch line on the same visit.
4. Remember what has already been tried. A stopper that was pulled and cleaned recently and clogged again points to the trap or the branch, which changes where we start.