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I’m a teenager who has never done anything even related to plumbing in the past, watching this at 12 am with 2 assignments that I need to do

"Is plumbing one of your interests?" "Nope" "Wanna se how to properly syphoning your drainage pipes?" "Oh you know me so well, dear algorithm!" Edit: for who did not catch it, it was implied that indeed I liked the suggestion, watched and liked the video, otherwise why bother to comment on it! 😁

The most common venting problem I've commonly seen is in otherwise properly plumbed bathrooms, the occasional kitchen, and in bar sinks: The trap dries out. Over many months or longer the water in the trap evaporates allowing the gases to pass in. If you have an unused bathroom, an empty apartment, a bar sink down in the basement that you haven't used in a while. Just set an alert on your phone for every six months or so to "Check the Traps." Then just run some water in the trap, flush the toilet. Don't forget laundry room traps that haven't been used in years. If the water is turned off. Just bring a bottle or bucket. It doesn't take much.

2:37 Neat fact, this vent that goes to your roof and lets fresh air into the system is the reason why you sometimes see the water in your toilet bowl sloshing around when it's windy outside. I always wondered why that happens, so I looked it up a few years ago.

S-trap drainage systems are very common here in Australia (also not illegal). When they are installed correctly with adequate ventilation from the initial install, they rarely malfunction.

In Finland, a special odor trap is used in toilet sinks, which is based on the s-trap, but the old s-trap is still used in the kitchen sink because it helps keep warm-seeking bugs and insects out of the house. Instead, installing pipes inside the walls should be avoided, because it is a risk of water damage if the pipe starts to leak or crack, allowing moisture to ruin the wall structures and insulation.

From an ex-plumber, you did a outstanding job explaining this subject. Keep it up!

I repaired sewer mains and services for 12 years for a large city, and every year we heard of more than one person dying somewhere working on a sewer system from inhaling poisonous sewer gases. Confined space permits along with safety equipment are now required by most cities, but someone always seems to want to take a short cut, and it can kill them.

You can also smell sewer gases in a bathroom that may not be used often (like a guest bathroom) when the water in the trap evaporates.

I do think my old house had this problem and never figured out how bad smells came out of the pipe. Thank you.

I worked in a lab that had 3 small sinks with aspirator faucets that nobody used anymore. We also had 5 machines in that lab that tested 10 medical gloves at a time for leaks. (Important that first responders, nursed and doctors do not contact sick patient blood!) Everyone was complaining about the stink from the glove testing machines, which seemed strange to me as I would stick my head over the tank at the bottom of the gloves being tested and it smelled like fresh water to me. After much debate and 3 meetings to determine what organism might be the culprit, I happened to be in the lab and heard a small gurgling sound. Took me a while to figure where it was coming from, but once I did the smell almost knocked me out. The water in the trap had evaporated over the years and was allowing low pressure sewer gas to vent out of these unused sinks. I filled all three sinks with water and a little cooking oil to slow down evaporation. Told my boss "I fixed the problem. No need for more meetings." LOL

I'm honestly kind of relieved that even though S-traps are illegal, you aren't legally required to change them for all the reasons this video brought up

Laundry room in the basement smelled like constant funk until I realized the utility sink hadn’t been used for 2-3 years. All the water had evaporated from the drain pipe. It’s vented, but that doesn’t help you when all the water’s gone.

1:34 "Pitha gore us"? Made me laugh, but there's some good info here.

That last mentioned Loop Drain/Vent system is often used in island sink installs since there aren't any walls at the island to route otherwise verticle vent pipes. Might be a good idea to check your kitchen/bathroom island sink(s) to see if you've been outfitted with one.

Good explanation of the system that will help many folks. A couple comments - bath and kitchen sink plumbing is usually 1-1/4" tough on our last house I did a mod to the tail pieces to the 2" wall drain piping. Secondly, I would be surprised if an 'S' Trap system on a reasonably new house wouldn't have DWV plumbing to the roof or at least a properly sited DWV such as the Oatey you showed that would prevent siphoning of the trap water

I’m going to get right on this in my home after I get my solar powered doorknobs installed.

Look, I’m a plumber, if you’re having issues with siphoning or evaporation or even pressure build up in the plumbing system that bubbles through your traps, you need to check a lot of things, the slope or grade of the plumbing, mainly that it is consistent, not up and down… the waste pipes need to be fairly clean, they can block up similar to your arteries, flow is important for pipe dynamics… The length of any waste pipe (not sewer) in my country is 3.6m from the trap to the outfall, which can be called a few names, I’ll use gully dish in my references. If you are over 3.6m you need to upsize your pipe to roughly 65mm, minimum, there’s still 80mm and 100mm in a typical home as other options, but a 65mm pipe can go 10m, you can add other fixtures to it like a bath,hand basin or laundry tub…before you need to install a vent on this waste pipe… every pipe above 65mm must be vented if it is 10m or more to the homes main drain vent, you can buy “vented traps” also, but as long as you also have a main vent on the house the drains are servicing, ie one main vent per dwelling. If you are banning ‘s-traps’ you need better plumbers, a trap is a trap, and each country has a code to how much water they shall hold. And there are also anti siphon traps for high velocity drain grades. It really is simple stuff… I’m surprised that you didn’t mention “through traps”. They are a straight piece of pipe with a rubber type hose in them, with no water at all…those should be removed, waste pipe fittings for baths and pools that are pleated plastic tubes are really bad at blocking, because the crap fills the grooves too. One more thing is there’s a limit to how deep a trap is, water can’t fall miles to the weir of the water, that will stink aswell. On top of the water could also force the trap to empty out with back siphonage.

I live in Thailand where S and P traps are essential to blocking the entry of ants and other insects into living quarters. They also allow retrieval of small objects dropped accidentally into a sink or toilet.

I watched this video when it first came out just out of curiosity, but had not done much plumbing. Over the last couple of years I've done a bunch of plumbing, so I decided to re-watch it when it came up in my recommendations again. Made a lot more sense. Thanks.

Here in England, we don't have those problems :) Fiirstly, the traps cannot be siphoned of all their water - the up part of the trap needs to be long enough to hold enough water to refil the trap once the air stops flowing. Also, whatever is draining usually still has remnant water in it that drains quite slowly - so this refills traps too. Secondly, much of our plumbing is NOT connected together ! Once the pipe has gone outside, it usually has a short spout on it pointing downwards into the next section of pipe. With the 2 pipes not being connected, it vents any sewer gasses - and this venting process occurs at floor level and ground level - so upstairs plumbing is vented twice before it goes into the underground sewer system. The only exception to this is the soil pipe from toilets. These are more like what you have - a vertical pipe going up to roof level, open vented at the top. Thes pipes can be used to connect other waste water pipes - but as their diameter is a fraction of the toilet soil pipe size, agin there is no chance of significant siphoning.

My favorite part was the animation of little turds leaving the houses.

This video only applies in the US - S traps are used elsewhere with other techniques (venting the whole system distally or wide bore pipes to prevent syphoning).

Ain't no way bro said pithagoreus

Big fan of your channel . My wife is a serial renovator. We have been reno fools for almost forty years. We do all our own work. Last year my son bought an old rough built house high up a mountain here in BC. Not occupied for ten years. Took a month to restore water from 5000 feet away from a cistern we had to hand dig. Just got back after two weeks replacing all the plumbing in the place. Your info gave us confidence we would succeed in the end. Thanks so much and keep the content coming.

As a home owner from Germany who has done some plumbing I appreciate the effort you put into your tutorials. Our home is former farm house build in the 1920s and has a dedicated septic system. The lid of this system has some holes to allow ventilation of the sewer gases. The waste water moves through three chambers before the mostly cleared gray water is pumped from the last chamber into a small pond with plants for biological reduction of the remaining substances (mostly nitrates and phosphates). Twice per year a sample of the grey water has to be tested in a lab or the home owner could lose the permit to operate such a septic system on the property.

My homeboy Pitha-gorass be rollin in him geave

Bro, Im not even a plumber I run my own hvac business and I cant stop watching your videos Im on a binge. Best plumbing channel I seen on YT idc I seen many videos and channels and yours is not only straight forward but visually pleasant, very informative and the timing of the video is perfect its short when need be or long when need be. Im 28 years old I'm not a old head or a youngin but your content is great for all age groups. I know enough about plumbing considering I install tanklesses, tanks, boilers, etc but I still learned a lot from your channel 👍🔥 Btw that 30 min tankless/combo video was just perfect for beginners and visual learners.

" Dammit Jim, I am a locksmith, not a plumber! " Excellent video. You not only explain the situation, but options on how to resolve.

WOW! Fantastic information. We built our home "off grid", with absolutely no knowledge, about 35 years ago (before the internet). No permits, no inspections, no brains. We had a problem with gasses from my septic system when we used our washing machine. I eventually got it fixed, but I never realized what was exactly happening..... but I did get it right.

Thanks an awful lot. I recently bought my first home and every bit of information I can get is helpful! Hope you had a merry christmas, have a happy New Year

Nicely done over all. Some clarification that I would like to provide though... A cheater vent or AAV does not have to be mounted above the flood level of the fixture. It does have to be mounted a minimum of 4" above the trap weir. This is at minimum true for IPC 2018 (international plumbing code 2018 revision) The reason for this is clarified when your diagram of the AAV is corrected. The open position of the AAV is the diaphragm pulling down and away from it's seat. The diaphragm (the little piece of rubber or rubberized material) that blocks the sewer gases in and is in the normally closed position and depending on the brand and age of the vent the rubber will be held in place either by its own elasticity or by a small spring. The diaphragm is able to let air in but not out when either negative or positive air pressure is applied. If you hold up an AAV to your mouth and breathe you'll find that you can only inhale and not exhale. Positive air pressure (exhaling) forces the rubber to seal itself even tighter against the plastic seat. This means that if the pipe further downstream becomes clogged and a back up is occurring then the positive pressure created simply seals the AAV even tighter. This means that the air trapped in that 4" long piece of pipe may get compressed but it is not displaced by the waste. This is called an air lock. Different AAV's are rated for different amounts of air input measures in CFM or cubic feet per minute, they are also rated for how much back pressure (positive pressure) they are able to hold back, measured in inches of water column. AAV 's do eventually fail as the rubber and/or spring wears out but they are threaded into place and thus easily replaced.

I now understand why we occasionally get septic gasses in our bathroom. I went crazy trying to figure it out, thinking our toilet wasn't seated properly or pipes weren't connected right. It turns out that our bathroom has a tub that isn't vented.

I always thought the trap was simply so you could potentially retrieve objects that might accidentally fall into the sink like a wedding ring or something. Now that you say it the sewer gas thing makes a lot of sense.

I must say this was very easy to understand. I am not a plumber, and wondered why the S traps are not used anymore. Thank you for your very informative video.

Hi from france Mind-bending youtube algorithm ! It takes me from "government officials telling fakes news" to plumbing installation. At least i learn something today in this topic ! ( although some one could find them entertaining, not sure "fakes news in politics" would teach anything valuable ) A thumb up and a new subscriber

I really enjoy your videos. As a plumbing instructor, I use your videos with Q&A worksheets for my high school students. These videos, combined with lecture, open response questions, and short quizzes using Kahoot really improve the educational experience for my students.

We are looking into remodeling projects, and this gave me a lot to research before I start! Thanks for the informative video.

Well, S-traps is more used than you think in most bathrooms. Way more. Even toilet closet is also mostly S-trap type. The only thing to reduce it is make fall part short as possible, or make somewhere corner to brake falling speed. The P-trap need done carefully, or you will have more residue in the horizontal part after some time.

No questions, I learned a lot. ☺️ I am glad the ban on "s" traps doesn't mean eliminating all "u" based traps, all together.

That was interesting. When I saw the thumbnail, I though, "yeah, don't we _all_ have S traps?" But after watching the vid, I realize I have P traps; and I completely see how P is better than S. So, nice job !!

Knew about a house sold. 2nd buyer, could smell something bad from one of the bathrooms. Here it was a sealed vent on the roof that wasn't taken off after the build. Easy fix. Thanks for the video

I'll file this in my mind under "Things Super Mario KNOWS that happen to be irrelevant in most princess-saving contexts".

Randomly recommended video to me just now, not what I was searching for, but neat and informative! Thanks for this! Good work! :)

Haven’t had issues with AAVs not passing inspection in Northeast Indiana. Still using S-traps at home because I’m lazy, but being in an old farm house, the sewer and gray water systems are completely separate.

Thanks for the information. I am a 'diy' homeowner that has rarely experienced the positive motivation you get from getting it right the first time. The mechanical principles of design tend to elude me and your video simplified so much.

This is literally the first time seeing something under the sink that wasn’t an S trap. I really need to renovate. This is why I tend to plug the drains

In Germany we have ventilation after the trap; they are called "Schnüffelventile" because they make this specific sniffing sound (very quiet though). They let air into the drain so the trap does not run out of water. They are common here.

I believe the 6" above flood line of the fixture is if using the AAV as a stack vent. If you already have a stack vent an AAV can be used on an S trap and only needs to be installed 4" above the top of the trap which should be able to go inside the vanity cabinet under the countertop. That is if your municipality allows AAVs. Many are just behind the times and don't care to change. Mine are working just fine.

In our country (NZ) this is catered for by installing a terminal vent at the head of the household drain system. Appliance "S" traps are normally deep enough to not lose the seal, but if a toilet is flushed on an unvented system then the weight of the 4" flow is more than enough to empty most appliance traps in the vicinity whether S or P. Install a 4" or 3" terminal vent and all syphon problems are solved.

Thank you for recording and posting this valuable educational video.

There are also mechanic traps that use a counterweight to close. Those work well in rarely used fixtures, to avoid the evaporation problem.

I find this interesting since I had to study plumbing for my teaching license. It was only basic, but traps were an important aspect of the subject. Oh yeah, I had the most fun with plumbing so I like this video. It's so fascinating.

Tyvm for this video. Very well spoken & presented in a way even I, whose plumbing experience deals with a plunger, a can of draino or digging longdrops out the back for my grandfather. He liked to change HIS thrones location, yes he built an actual throne for his outhouse. Now that man could do anything to do with a house. I miss that crazy bugger. I don't miss his pet snake that lived in the outhouse tho lol.

The trap arm has a maximum length depending on the size of the pipe. An island vent or loop vent can connect under the floor but has to connect to a wye and not a tee at least 18 inches downstream and the wye has to roll up at least 45 degrees from the horizontal.

You’d think that, with so many household repair and other issues being physics-related, they‘d teach physics to kids in this practical context. Thanks for the video!

Huh. I’ve seen vent pipes on roofs many times and always assumed they had an open connection into the roof space. Never suspected they were connected to the drain pipes and for this purpose. This video gave me good information that I didn’t previously have. A well earned thumbs up is in order

Well I learned something here. Even though plumbing fixtures were not even on my mind at all. Now I have to go look under the sink to find out if I have a P or S trap.

Thanks G2L nice visual of vents for plumbing. Imma go take a look around my house now. Can you do topics on air condtioning and electricals?

Very good knowledge properly explained. I enjoy simple straight forward explanations, and advice. Thanks. Now I can fix

This answers my childhood home problem. Many times the dishwasher would drain and the kitchen sink next to it would have air bubbles and bits of water come out along with a smell.

This one goes to my "unrelated knowledge" brain folder, regardless of me never doing anything related to plumbing in my life

Great video. S-traps are legal and very common in Australia. I was wondering why plumbing is different in American renovation videos.

very clear and concise explanation. thanks! at the loop vent, couldn't we direct that anywhere? i mean, does it have to go downward? maybe a hybrid of the two venting solutions? just have a straight to the roof vent?

Great videos as always, I have an S trap under my kitchen sink and I put an oatey sure vent But I couldn't get it above the sink line because it's underneath a granite counter. So I made it as high as I could, decided to do a little experiment and I removed it and replaced it with a cap and a clear trap. Turns out it doesn't siphon the water out. Still thinking about opening the wall on the other side and running a vent up through the roof.

Wow, this just explained why my one bathroom smells when ever the water is running. 1950s plumbing, sink still has an S-trap. Whole house shares one vent.

Nice detailed overview of drain traps. Tysm

Great vid. I've always wondered about vents, now I understand.

Awesome content! Never thought I would be so interested in plumbing. It has helped me with a ton of projects at home and at work. Your videos have helped me make my plumbing work look super professional. Keep it up!

Always a great channel to learn something you didn't know, or were not familiar with. Good job, thanks for the info!!!!

Do you have any videos on making PVC to cast iron hub connections? To convert the S-trap of the built-in lavatory in our powder-room to a P-trap, a 1-1/4" trap arm would have to be extended 15 inches over to an interior wall and then down inside the wall into the basement directly below, where it would then connect to a hub on a 4" cast-iron waste-vent stack about 48 inches away.

I work shipping and receiving all these types of things this actually helps me understand a bit more of what I'm looking at thank you

Beautifully explained. Thank you in part of all professional plumbers out there.

Thanks again for your videos. I wasn't familiar with the loop vents so I learned something new. You're an awesome dude!

Weird how I stumbled upon this while looking up plastic sheeting thickness. Anyway, thanks, yes I learned something unintended by the video. I learned why my P trap is venting gas into my right side kitchen sink. I usually just keep it covered with the drain trap and don't think about it much. So it must be siphoning out and the vent on the roof must be clogged again (maybe with leaves). Need to really snake that out good.

Straight good explanation. Good diagrams and animations. Thanks

Nice vid as usual. In the UK, plumbing is different, every house has a 4" vented pipe extended 1m above the highest window, into which all other connections are made, preventing any pressure / gas build-up from the mains. Obviously in a crowded city with old buildings in the US, that is hard to achieve.

What he said: "Excellent video. You not only explain the situation, but options on how to resolve." I had not heard S-traps were not allowed; thank you.

That was unexpectedly very interesting!! Thank you!

Thanks so much for this. You saved me from making a venting mistake on a reno! Awesome advice! \

Great explanation! I've done hospital plumbing for years and thought that the S trap was to access valuables accidentally dropped into the drain or to assist unclogging the drain!-John in Texas

This is a good explanation and I didn't know the connection between the greedy glass and traps. The diagrams make it clear. Methane is considered non-toxic; you may have meant hydrogen sulfide, the chief concern in sewage venting. Ammonia is toxic in high amounts. Methane can still be dangerous if it ignites, or if there's enough to displace the oxygen in an area. Carbon dioxide can also build up and displace oxygen, but really if you have that much methane or carbon dioxide you're probably going to smell the hydrogen sulfide (rotten egg or boggy smell), since our noses are generally highly sensitive to sulfur compounds. I will just add that I knew nothing about plumbing and watched some other Got2Learn videos before installing my own water heater. The videos really taught me a lot and the water heater has done great for many months now. The videos about recommended tools and tips & tricks were very helpful, as I had no experience going in.

Here in Australia we have vent pipes on the end of the stack, AAV'S (air admittance valves) where rooftop vents aren't possible.

Thanks! That was very clear and helpful.

Thank you for clear explanations of the pipes my man. Much love.

'S' traps are common in the UK, especially under kitchen and bathroom sinks. I'm not a pro but am an experienced DIYer, but I've never heard of any problems with them. Then again, we don't have the same strict codes here. Lots to think about though; as usual the most informative plumbing video on the subject. 👍 🇬🇧

Very interesting... I never studied plumbing before. Fascinating...

We only use p-traps in apartment blocks and hotels etc. Our detached houses use separate open systems for grey water and black water until they join at the main sewer line. The only reasons we need to use traps, in the grey water system, would be to catch any valuables which accidentally go down a drain and to limit the ingress of pests. Our black water lines are double vented open systems.

Great video. Although I can't speak for the whole of the UK, I can say that all the houses and flats I've lived in or know, have no direct link between the domestic waste water, i.e. from sinks and baths/showers and foul waste, i.e. toilets. Each of these facilities drain seperately out of a home with the two independant flows only coming together in an inspection chamber below ground level away from the house.

When I purchased a home with some plumbing issues, it taught me a lot about plumbing. The most important thing I learned was that any time that water in your pipes needs to go down, you need another pipe to go up to vent it. If your plumbing isn’t properly vented, you will hear and hear it gurgling and glugging as the air that the water displaces on it’s way down makes it back up through the path of least resistance. It makes perfect sense if you consider the fact that it’s the same reason you can put your finger over the tip of a straw, and the liquid from your beverage will remain locked in place until you release it. Knowing this explains why siphons work, and more importantly why shotgunning a beer works. It’s also why you need to let the air settle out if a beer bong before it will work, if you don’t you will choke on air and beer and look silly. Once you’ve bled the system and relaxed your throat, the power of gravity and hydraulic pressure will power that beer down your throat faster than you can even think about swallowing or choking. Another cool trick is to use a long bendy straw with a glass bottle. You put the long end down to then bottom, then you form a seal around the top with your finger wrapped around the opening and the small end of the straw. If the straw is long enough, you’ll be able to chug that bottle way faster than any of your friends, and look like a genius. So, anybody who tells you that drinking a beer with a straw isn’t cool or manly, then tell them that they’re just doing it wrong, and if you’re in a winning mood, bet them that you can drink a beer with a straw faster than they can without one. Once you used this trick to make them look foolish, you can laugh in their face and yell “SCIENCE!” before collecting your winnings.

That vent may explain how insects and other critters end up in drain pipes. That AAVsounds appealing as its interior vent location is relatively critter proof; it doesn't provide them with access from outside.

Thank you for this. I would be interested to know what software you used to provide the zooming in and out effects.

I believe there has been a change in the plumbing code that allows the s-trap if the 1 1/2" pipe goes into a 2" vertical, as that would break the siphon.

This is an excellent presentation and very thorough! Every home inspector should be watching this channel so that he/she can give comprehensive responses to homeowners who have questions as to why something is incorrect or requires a fix. Thumbs UP! as always!

I learnt something, thank you!

We have a similar problem in our home in Turkey. Here the problem is in floor drains of the bathrooms and shower basins, which are a standard design effectively incorporating an S trap method of repelling the gasses. But the water traps are shallow and we find are often empty, allowing the gases to fill the house. We are not sure if its as a result of evaporation or siphoning. As is in an apartment block, the landlords say it can’t be resolved. Interested to know of any recommended solutions for this as the gases are overpowering at times.

As an Australian licensed plumber I can refer you to Australian standard 3500 S traps I use university in Australia with no problems provided the standard is followed with the correct size for the number of fixture unit

My kitchen sink has an AAV. It works great. They last for decades.

Had one in our kitchen. Jerry-built house with lots of odd features. I remember the thing would suddenly start "gu-gunk-gunk-gunk"-ing at any time of the day or night.