You know you have a P-trap by looking under your sink or tub: it's the U-shaped pipe (or sideways P) with a horizontal arm going into the wall, holding water to block sewer gas. For toilets, if the drainpipe goes into the wall, it's a P-trap; if it goes into the floor, it's an S-trap (older style). Every fixture should have one, creating a water seal, though the toilet's trap is built into its base.
The P-trap can be found under most fixtures. Common places you will be able to see the p-trap are under both your kitchen and bathroom sink. If you have an laundry tub/sink you will be able to see the p-trap under that as well.
A P-trap, also referred to as an intake trap or preventer trap, is a U-shaped pipe commonly found in toilets or under sinks. The shape of this pipe allows it to hold some water, forming a barrier that stops sewer gasses from seeping into your home.
P-traps, named after their shape, contain a u-shaped bend that filters wastewater as it enters a plumbing system. The trap is connected to a sink, bathtub, and shower with a J-bend on one end and exits into your drainage system. The J-bend is the section of the p-trap that resembles the letter J.
You can identify the trap type by checking the outlet. If the pipe goes into the wall, it is a P-trap. If it goes into the floor, it is an S-trap.
S-traps are generally not allowed (non-compliant) in new Australian construction and major renovations due to risks of siphoning sewer gases into the home, but they might still exist in older homes where they were once common and are not illegal to keep in existing properties unless replacing fixtures. Modern Australian plumbing codes mandate P-traps (which connect to the wall) for new builds, as they provide better venting and prevent the water seal from breaking, ensuring safety and preventing odors and pests.
Most modern homes are equipped with simple P-traps. These traps are U-shaped pipes located underneath home drains that remain filled with water at all times. The water in these traps blocks sewer gases before they can enter your home through your fixture drains.
How to unclog a drain beyond the P-trap
Without properly functioning P-traps, your living spaces would be filled with the unpleasant odors of sewer gases and potentially harmful bacteria. The primary function of a P-trap is to create a water seal between your drain and the rest of your plumbing system.
Power Pro Plumbing offers fast, affordable P-trap repair and replacement for those who prefer not to attempt a DIY approach. Our LA plumbing technicians will ensure that the new P-trap is installed correctly so that you don't have to worry about any potential problems.
Common fixtures that require P-traps
All plumbing fixtures that connect to your drainage system require P-traps, including: Bathroom sinks and vanities. Kitchen sinks and garbage disposals. Utility and laundry sinks.
They usually join at a main sewer line. This connection is essential for removing waste efficiently from your home. A clog in the shower drain can sometimes impact the toilet. Both share the same drain line which can lead to slow drains or backups.
The primary tools for maintenance are a bucket and adjustable pliers. Place the bucket underneath the trap, loosen the nuts at the ends of the P-trap, and remove the trap by sliding it down to release the contents into the bucket. The final step is to check for any blockage in the pipes and then clean them out.
All of your showers, bathtubs and your washing machine also have P-traps down underneath the drain.
All floor drains, including cellar drains, shall be trapped. Floor drain traps shall be located at such depth below the drain inlet as to be readily accessible for cleaning.
Use a circular saw to cut away the subfloor to gain access to the P-trap. Make your cuts along the floor joists so that you'll have something to support the new subfloor. You may need to use a reciprocating saw to split the piece in two before prying it up.
P-traps are typically located under sinks, showers, or bathtubs. If your drain connects into the wall rather than the floor, you likely have a P-trap.
Pouring boiling water down the drain can help in certain situations, but it's far from a cure-all. In fact, depending on what your pipes are made of and what's causing the clog, it could even cause more harm than good.
Unclog a Sink With Vinegar and Baking Soda
Unlike surface clogs, which affect individual fixtures, a deep blockage impacts multiple drains at once, leading to more serious plumbing problems. If you notice slow drains, unusual backups, or foul odors, these could be signs of a deep blockage that requires immediate attention.
We highly recommend this practice, and often people ask “why pour salt down the drain?” The answer is that salt will break down grease and emulsified fats by itself, and especially when combined with vinegar and hot water it can contribute to clearer pipes.
Common P-trap problems include leaking pipes, clogged drains, and escaping sewer gases. Leaking pipes. If your pipes are leaking, the first step is to ensure that all connections are tight and have been installed properly. If there is a leak in a connection, remove the P-trap and reinstall it.
If your toilet bubbles or gurgles when you run your sink or your shower, you may have a clogged sewer line. Lastly, watch what happens when your washing machine drains. If you had a clog, your toilet could overflow, or water could back up into the shower once your washing machine drains.
For example, if traps aren't cleaned thoroughly at least once every three months, you can run the risk of your drains becoming so clogged that you experience a backup.