Most plumbing stores sell complete plastic P-traps, which include the trap itself, a trap arm and a drain opening adapter. These pieces are joined by a slip nut and washer that is inserted into the tailpiece or waste pipe.
Because the undersink area is jostled and bumped, these connection points can break or become misaligned. This can cause the trap to clog with soap scum or the drain to overflow.
Safety First
The curved section of the drainpipe under your sink, the p-trap (the name comes from its shape that looks like a letter P), holds water. This water seals the trap to prevent sewer gases from entering your home. The curved section also scoures itself to remove gunky waste. If you have a P-trap that isn’t functioning properly, you need to replace it to protect your health and your home.
You can buy a new sink trap assembly, often sold as a kit, that includes the trap bend and a trap arm. The kit may also include a plastic trap adapter, a rubber transition coupler and a section of plastic pipe. Cement is included with the kit for joining the plastic pipe to the old metal drainpipe.
When you are ready to replace your sink trap, put a bucket under the piping to catch any gunky water that will spill while the assembly is removed. Unscrew the clean-out plug, if it has one, from the bottom of the curved portion of the trap and empty the sink before disassembling the pipe.
Use the tongue and groove pliers to loosen the slip nuts integrated with the curved trap bend to the trap arm and sink tailpiece. Once the nuts are loose, the drain parts will slide off. Set aside the slip nuts, washes and old drain parts. Then, put your new trap kit on the counter and lay out all the parts.
Preparation
The drain trap is the loop of pipe that surrounds the sink, tub or shower drain, and it’s an important part of your plumbing system because it prevents sewer gases from entering your home. A clogged or improperly functioning trap can allow sewer gases to seep up through the sink drain, which can cause health issues and water damage to your flooring underneath the sink. While it’s easy enough to clear a drain blockage with a plunger, sometimes a corroded or leaky trap requires replacement. Fortunately, you can do this yourself in about 15 minutes if you prepare properly.
Start by loosening the slip nut washer (a beveled vinyl nut) and slip nut on the vertical tailpiece that drops down from your sink drain. Loosen the curved drain trap bend’s slip nut as well. If you use a tailpiece extension, remove it now too.
Once you’ve removed the old trap parts, set them aside in a bucket to catch any debris or water that spills from the pipe connections as you work. Next, empty your sink and toilets of any water, and shut off the hot and cold water valves under your sink.
Check the new trap for any crooked or leaky joints, and straighten as needed. The slip joints are designed to seal only when the sections of pipe run parallel with each other. If the joint is leaking, loosen the nut and carefully straighten the section of pipe to repair it. Then retighten the nut.
Loosen the Slip Nuts
If your sink is constantly clogging, it may be time to replace the drain trap. Over time, the metal parts of a drain trap can become corroded or rusted, causing a buildup that will cause your drain to slow down and release foul odors. Fortunately, replacing your sink’s P-trap is easy enough for any homeowner to do. All you need is a bucket, a wrench or channel lock pliers and a few other tools.
Start by positioning a bucket underneath the trap to catch any water that might spill as you loosen the slip nuts. Next, plug up the exposed opening of the drain line with an old rag to prevent sewer gasses from seeping into your home. Then, use a wrench or channel lock pliers to loosen the slip joint nuts found on either side of the “j” bend of the trap. Once the trap is fully loosened, it should pull free and should be drained of water.
Using a bottle brush or bent wire coat hanger, clean out any hair, gunk, or other debris from inside the drain trap. It’s also a good idea to use this opportunity to clean out the entire pipe section that leads up to the wall fitting.
Remove the Trap Bend
The curved portion of pipe that extends from the drain in a “J” shape is known as the trap. It retains a small amount of water to prevent sewer odors from entering the house and catches stray hair, earring or other objects that might slip down the drain. Over time, debris can build up in the trap and cause the sink to drain slowly. If you suspect this is the problem, it’s easy enough to clean out the trap and restore proper drainage to the sink.
First, put a bucket under the old drain trap to catch any gunky water that will spill when you loosen it. You’ll also need a wrench or channel lock pliers to loosen the slip nuts on each end of the j-shaped trap bend. Attempting to unscrew them by hand may damage the metal finish on the trap. Place a rag over your tool to prevent scratching.
Once the slip nuts are loose, slide off the curved trap bend. This should be relatively easy, but you might need to wiggle it slightly. Once the trap bend is removed, set it aside and empty the bucket. You can use the two washers that were part of the slip nut connection to connect the new trap to the drain lines – much like how Lubbock plumbers do it.
Remove the Waste Arm
It’s quite common for household sink drains to become clogged with hair, soap scum, and other debris, leading to slow or no drainage. One of the most common culprits is the curved length of pipe known as a P-trap, found under every sink in your home. The trap is designed to “trap” water and keep it from flowing into the sewer system, but if it becomes too full it can cause a backup which requires you to remove the trap for cleaning or replacement.
The first step to removing the old trap is to position a bucket under it to catch any water spillage you may make as you loosen the slip nuts and disconnect the plumbing. Also have a bottle brush or bent wire coat hanger handy to clean any gunk from the inside of the trap as you unscrew it. You should also have a pair of rubber gloves and safety glasses available in case you encounter any chemical spills as you work, or if the space underneath your sink cabinet is cramped and hard to navigate.
Next, use a wrench or channel lock pliers to loosen the slip nuts integrated to both ends of the curved trap bend (the J-shaped part connected to the sink tailpiece and the sink trap arm). The trap bend should slide off fairly easily, but if it doesn’t, lightly wiggle it until you can remove it. Once removed, set aside the slip nuts, washers and old drain parts.
Reassemble
The space under a sink cabinet is often dark, so it’s important to have a bucket handy to catch spills. A small work light helps, too. Loosen the slip nuts integrated to the curved drain trap bend, then slide it off the sink tailpiece (a bit of wiggling may be needed). Next, loosen and slide off the waste arm from the opening of the branch drain. Set the old trap parts aside.
If the curved drain trap is equipped with a cleanout plug on the bottom of the curved section, remove it. If not, just pour water out when the trap sections come free.
Once you have your replacement trap assembled, use PVC primer and pipe cement to glue the reducing coupling to the drainpipe coming from the wall. Depending on the make and model, these PVC fittings can be tightened by hand or with pliers, but don’t over-tighten — half a turn is usually sufficient.
Finally, connect the new trap to the reducing coupling with the washers on either end of the slip nut connections. Then, tighten the slip nuts by hand or with pliers, making sure to check for alignment along the way and not over-tightening. Once the nut is secure, test the P-trap by running water in the sink and looking for leaks. If you see a wet spot, the drain assembly may need to be tightened or rebuilt.