Clean Out Your Bathroom Sink Trap

Ever dropped your wedding ring down the drain? Or maybe your sink is just draining slowly. You don’t have to call a plumber for this. You don’t usually need any tools for this task, though a channel-lock plier can help with a stubborn joint. First, get a bucket large enough to go under the drain and all the way to where the drain pipe connects to the drain outlet at the wall. If you’re worried that someone might try to use the sink while the drain is out, turn off the two water valves. I try not to mess with these valves, if I can avoid it; because an old valve can start leaking after being turned off and on.
Place the bucket under the drain and loosen the three or four plastic “nuts” on the drain pipes. The drain piping is usually either 1-1/4 or 1-1/2 inches in diameter. There may be both sizes with an adapter somewhere.
If you dropped something into the drain, it may be in the trap or it may still be in the tail piece or stuck on the stopper (if present).
As you take the drain apart, remember where each part was. I recommend taking pics before disassembly to help with reassembly. There may be an extension on the tailpiece that comes out of the sink drain and extends down to the trap, if the tailpiece is too short to reach the trap. If you have this extension, you can leave it attached to the trap. Loosen all of the other nuts completely. I separate the end of the trap first and let it drip into the bucket. The connection at the end of the trap usually does not have a seal, as the sealing surface is built into the exit pipe. Turn the trap about the tail piece and pull it down off of the drain. The nut and seal should stay on the tailpiece. If they start to come off, push them back up. Note that the seal has an orientation such that the taper seals against the trap pipe end. The nut presses against the flat side of the seal to force the taper into round of the trap. The trap can be turned and emptied at this point as you search for anything that may have fallen into it. Separate the extension (if present) after emptying the trap. There should be a seal where the extension meets the trap. I keep the seal and nut on the extension, like I did at the tailpiece. Also remove the exit pipe from the outlet. There should be another seal there that stays on the exit pipe with the nut.
If there is a stopper in the sink that is actuated by a vertical rod behind the faucet and a horizontal actuator connected under the sink, loosen the nut that holds and seals the horizontal actuator into the tailpiece and remove the actuator from the tailpiece. Now the stopper should pull out of the drain. As you pull out the stopper, look again for anything that fell into the drain that may have been trapped by the stopper or hung up on the overflow escape path. The overflow path is an opening inside the tailpiece just below the stopper that allows water that reaches near the top of the sink to flow inside of the sink down into the drain. Any small rod, such as a screwdriver, can be used to pull anything stuck in the overflow passage into the tailpiece to fall into the drain and bucket below. This is also a good time to clean the tailpiece with a brush. If you left the supply valves open, you can flow a bit of water to rinse debris down into the bucket. Also clean off the stopper.
The stopper and actuator can be reinserted now. With the stopper down and the hole at the bottom facing forward, insert the horizontal actuator rod downward so as to engage the stopper hole and tighten the nut on the tailpiece enough to seal the tailpiece but not so tight as to restrict the operation of the actuator. You should be able to actuate the stopper with the horizontal rod. Then, reconnect the vertical rod and adjust the connection, if necessary to allow closing the stopper and opening it fully using the vertical rod.
Next scrape any debris at the drain exit into the bucket. Any debris that goes into the drain exit should go out the main drainpipe once the drain is reassembled and water passes through.
Take the bucket and clean out all of the pieces. You can brush them out or blast water through to clean them. Bring the clean pieces back inside and reassemble the drain. First slip the trap (with extension, if present) onto the tailpiece. Make sure the seals are in place and oriented with their flat sides toward the nuts. Slip the exit pipe onto the exit. Then adjust the extension and trap to a height that allows the trap to connect to the exit pipe. Tighten the nut loosely and adjust all pieces to fit without tilting. Tighten all of the nuts by hand only. Do not use a wrench unless the connections leak.
Open the supply valves if you have them closed and run cold water through to check for leaks. Tighten any leaking connections. Do not over-tighten the plastic nuts. If they are leaking, take them apart to see why. Replace any damaged parts.