The P-trap is the P-shaped section of pipe in the line that runs from the bottom of your sink to the wall. It's shaped this way to trap sewer gasses and prevent them from coming out the sink as well as to catch debris that's been washed down the sink, such as hair or food scraps.
A blocked p-trap will cause water backflow to occur. The first sign that your p-trap is clogged is when the water in your sink takes longer than average to flow down the sink. In the case of a clogged P-trap, it is best to place a small bucket under the trap with the water shut off.
The p-trap for showers is located underneath. Like the other fixtures, the shower drain p-trap prevents sewer odors from escaping your pipes.
First, if you have metal pipes, pour boiling water down the drain. Then remove hair from the drain. If that doesn't work, use a mixture of vinegar and baking soda. If the clog persists, use a plunger, plumber's snake or chemical drain opener.
This pipe is U-shaped, and it helps to collect and drain water. This helps to prevent odors and gasses from coming back up the pipes and into your home. Over time, your P-Trap can start to smell due to build-up and you will need to clean it. Cleaning this pipe will help you to avoid costly repairs in the future.
In a nutshell, a p-trap is a u-shaped bend in the waste pipe that connects a sink's drain to a home septic tank or to a municipal sewer system. Under normal circumstances, p-traps always contain some water.
If you don't run any water down the drain for a long time, the water inside the P-trap will eventually evaporate. It usually takes a month or more before the trap will fully dry out. However, the problem is more common in dry climates or during the winter when you're running your furnace constantly.
Plumbing codes require a P-trap be installed anywhere there is an open drain line that expels wastewater into a drain waste-vent system. The P-trap traps solids that can clog the drain or sewer line. The P-trap stops sewer gases from backing into your home through the drain line.
If you look at the drain pipe under your sink, you'll see a curve in the pipe that resembles the shape of a “U” or a “P.” That's an example of a P-trap. A P-trap is a bend in a drain and waste pipe with a specific purpose.
The difference between the two traps is simple: the shape. An S-trap flows down from the drain, curves up, then curves back down. The P-trap also flows down from the drain and curves, but the curve finishes on a horizontal pipe that takes the waste out.
To eliminate odors coming from a dry p-trap, pour half a gallon of water into the trap to restore the barrier. It will prevent the odors from seeping through the drain. Another helpful method is to add a cup of white vinegar bleach to get rid of larvae and slow down the evaporation.
Toilets have their own built-in traps, and so do floor drains. The trap on a floor drain is located below the surface of the floor; the photo below shows a floor drain as seen from the side.
It is easy to fix a P-trap that ran dry due to a period of inactivity. Flush the unused toilet and pour water down the sink and bathtub drains to restore the P-trap's water barrier. Run water down the infrequently-used bathroom drains regularly to prevent the P-trap from running dry in the future.
There are several common causes for a sewage odor coming up from the shower drain, including a clog in the drain line, a dry or dirty P-trap, mold or biofilm build-up, and leaking drain lines in the walls, ceiling, or under the floor.
According to the International Residential Code, the maximum vertical distance between the sink drain and the entrance to the p-trap is 24 inches. Be aware that it'll make a fair bit of noise dropping that far.
P-Trap Repair Costs
A P-trap repair will cost around $275.
A drain snake, also known as a plumber's snake—is a retractable, flexible drilling tool you can pick up at hardware stores. You'll use the snake's hand crank to send a metal wire down your drain to either break up or pull out whatever is clogging it.
Use baking soda and vinegar:
Firstly, pour a cup of baking soda down the drain and then after a few minutes pour a cup of vinegar down the drain as well. After a couple of hours you can turn the shower on and see if the blockage has been dissolved. Then add boiling water again to clean out thedrain.
Dry air might just be the cause of that unpleasant rotten egg smell in your home. Especially during winter, a P-trap can dry up and allow sewer gas to enter the home.