Overall, there are very few parts of your Richmond home’s plumbing system that you can easily view. One component that you can often see is the P trap that resides below every sink in your home. Does a P trap serve any purpose other than making it more difficult to store items in an under-sink cabinet, though? The truth is that P traps are exceptionally important and make much of modern plumbing possible. To learn more about all that P traps can do, check out these insights from our experts at Davis & Green.

Composition of a P Trap

A P trap consists of three main parts: the inlet, outlet, and trap. The inlet is a straight pipe that comes from the drain in the sink, shower, or other plumbing fixture. The trap is the P-shaped pipe that collects a small amount of water in the curve. Finally, the outlet is the pipe that attaches to the main drain line that allows water to flow out of the plumbing fixture. P trap drains can be made out of PVC, galvanized steel, or even copper. The three parts of a P trap are held together by compression fittings. This makes the assembly easier to take apart if you need to clean out the P trap.

Stopping Methane in Its Tracks

The first and most important duty of a P trap is to prevent methane from coming into your home from the sewer line. As waste exits your home and the homes of your neighbors, it begins to decompose. When this occurs, the sewage releases methane gas. Methane can cause negative health outcomes if it collects in your home in high concentrations. Additionally, it can be flammable and even explosive. A P trap blocks methane by retaining a small amount of water in the trap portion of the pipe. This water is just deep enough such that no gas can pass through from the outlet to the inlet. Additionally, since methane is a heavy gas, it is difficult for it to dissolve in water. Therefore, this simple water seal is quite effective.

Protects Against Clogs

Another benefit of P traps is that they can trap items that can clog drains. Although the P trap will become clogged and cause temporary drain problems, the P trap is much easier to clean than the rest of the drain. With the items stuck in the P trap, they can’t continue down the outlet and potentially clog your main drain, a problem that would require a visit from Davis & Green. Since the P trap is so close to the drain opening, it’s easy to get drain snakes to the clog to restore normal operation. A side benefit of a P trap is that if you accidentally drop items down the drain, there’s a good chance you’ll be able to get them back because they’ll likely stop in the P trap.

Problems With Evaporation

One problem with using water as a protective shield against methane is that water eventually evaporates. Normally, this isn’t a problem because you replace the water in the P trap every time you use the sink or other plumbing fixture. However, if you have a P trap in a rarely used room, the water in the P trap can evaporate and allow harmful gases through. To prevent this, all you need to do is run water for a few seconds in each of the fixtures. In a sink, you should be able to use a flashlight to look down the drain and see standing water in the P trap. For vacation homes that you’re closing up for a long period of time, Davis & Green recommends using RV antifreeze to protect your P traps and other pipes.

Cleaning a P Trap

Cleaning a P trap can be done in a number of ways. Some P traps have a clean-out located at the bottom of the trap’s curve. Our experts can remove the cap from this clean-out to allow small debris to flow out of it. This is also a great way to remove excess water prior to removing the P trap itself. For clogs that won’t fit through the clean-out, we can remove the P trap assembly. Typically, we unscrew the nuts on the compression fittings by hand to release the trap from the inlet and outlet pipes. We make sure to have a bucket underneath the trap to catch any water or debris. We also may use a drain snake to go down the inlet and into the P trap to break up debris or pull it back out of the drain. Davis & Green does not recommend chemical drain cleaners to clean a P trap because they can damage the drain pipe.

The Dreaded S Trap

Just like technology advances over time, so do plumbing techniques and standards. If you have an older home, you may notice that your P traps have an extra “tail.” These traps are actually called S traps and used to be the standard for residential and commercial plumbing. Unfortunately, because the second bend in an S trap rises as high as the first bend falls, an S trap can start a self-siphon that removes the water from the lower bend. This opens the drain to potentially allow methane gas to pass through. S traps are now against local building codes across the country. If you investigate your home’s plumbing system and discover one or more S traps in your home, be sure to call Davis & Green right away to have them replaced.

Protecting the P Trap

There are many steps you can take to protect the P traps in your home to help prevent clogs from forming. The best thing you can do is to carefully observe what you put down the drain. Items like grease and oils, eggshells, coffee grinds, and other harsh food items can become trapped in the P-trap and cause foul odors and inconvenient clogs. Typically, the only things that should pass through most P traps are water, soap, and dirt. You can also clean a P trap monthly using a mixture of baking soda, vinegar, and water. First, put a healthy amount of baking soda down the drain. Next, follow it with enough vinegar to cause bubbles to rise out of the drain. Finally, rinse the drain using hot water. Following these steps will help prevent buildup in your P traps, and it will keep them smelling clean and fresh.

Problems With Large P Traps

Many times, when a do-it-yourselfer installs a P trap, they assume that bigger is better. However, this isn’t the case when it comes to P traps. P traps that are either too deep or too long can collect too much water to the point that any debris that passes through the drain won’t get washed away by the pressure of the water draining from the sink or tub. This will inevitably lead to more frequent clogs that are harder to remove. Additionally, as the debris sits in the water and decomposes, you will notice foul odors permeating the air in your home. P traps should be deep enough to create a water barrier and shallow enough to replace that water every time you use the associated plumbing fixture.

Addressing Plumbing Needs Big and Small

At Davis & Green, we work hard to keep your home or office’s plumbing system working great. That’s why we offer drain cleaning and repair services, sump pump installation, and water heater repair. We also offer electrical installations and repairs, generator installation, furnace repair, air conditioner installation, and much more. For over 35 years, residents throughout the area have trusted us to take care of their home comfort needs. This trust is reflected in the five-star customer reviews that we receive. To learn more about your home’s plumbing system, contact us at Davis & Green today.

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