Find out how to clear a clogged drain. Learn why chemical drain cleaners don't always work as well as people expect. Get tips on using drain snake, or, in the case of a main-drain stoppage, hiring a professional to use an electronic drain cleaner.
LESLIE: Well, drain clogs  can be a real hassle of home ownership. They happen at the least convenient moment and they can be a real pain to fix.
TOM: True. But they do come with the territory and they don’t have to be complicated to free up. Here to explain the solutions is Richard Trethewey , the plumbing-and-heating expert for TV’s This Old House .
RICHARD: Hello, gang.
TOM: It seems to be the most common thing for homeowners to do to fix this is to reach for the chemicals. But that’s not always the best approach, is it?
RICHARD: Well, I’m a licensed plumber. I would never use the chemicals . People do it. It’s a big industry. They can at least do it to do maintenance. But if you have a real solid clog, particularly in a kitchen sink  that is loaded with you name it: celery and all sorts of heavy-duty garbage …
LESLIE: I believe they call that “biofilm.” Ugh.
RICHARD: That these chemicals are not going to necessarily be able to clear that.
RICHARD: And so, to me, the best way is to do some sort of mechanical clearing using a proper snake. But it’s a big industry and it’s – people do it, you know? We often – when we used to be brought in to – when I was brought in to clear this things after the fact, the chemicals became a real terrible thing for us because we had to deal with this caustic stuff and try not to burn our hands, yeah. But it’s …
TOM: All the chemicals that they put in before they called you.
RICHARD: Yeah, that’s right.
TOM: They would fill these drains up with chemicals and then …
RICHARD: Yeah, yeah. Come to this nuclear waste department. So, clear it now, please.
LESLIE: And it can’t be good for the plumbing.
RICHARD: Well, if it sat for too long and it was a thin-wall brass pipe, it could wear it out. I don’t want to say that all the chemicals are going to wreck the plumbing.
RICHARD: It’s just I don’t think it’s effective as much as people think it is effective, on these chemicals.
TOM: So let’s talk about what is effective, starting with the mechanical clearing methods. Baseline defense: plunger, right?
RICHARD: Yeah. I don’t – every house should have a plunger. I think the toilet stoppage …
LESLIE: The grossest tool in the house.
RICHARD: It’s a great tool.
LESLIE: It’s pretty gross.
RICHARD: No. Well, you do have to wash it once in a while but it is really a terrific tool and every house should have one. Particularly, as toilets get smaller and smaller water content, the passageways get tighter and you have to find ways to clear it.
And what we’ve shown a couple of times on camera is that people tend to think they want to plunge and push the stoppage down. You actually want to get the plunger down over the lower part of the bowl and actually create a little bit of a vacuum and pull backwards to clear the stoppage back towards you. It’s a completely counterintuitive move to ever say, “Let’s pull this back towards me.”
TOM: Right. You’re not pushing it – yeah, you’re not pushing it back down the pipe; you’re really pulling it out to give it a chance to go down on its down again.
RICHARD: That’s right. Right, right. That’s right. That’s right. That’s right. So the plunger is an important tool that every house should have.
And the other is – they’ve now got, at the home centers, these beautiful, little drain snakes : a little hand snake that can feed by itself. As you turn the drum, there’s a trigger that can allow you to not have to put your hands on it. And so now it’ll advance. And every house should have one of those, so you could go down through – on a kitchen sink, you could go down through the trap and right to the horizontal part of the kitchen drain, which always tends to clog because of the food products in there.
And just – now, when you get that down in there, then you run the water while you’re spinning that snake, you are cleaning that inside of the pipe like no chemical could ever do and just get – yeah, get it all down the drain, yeah.
TOM: And washing all that debris down at the same time.
RICHARD: It’s the effective …
LESLIE: If you improperly snake a drain, can you do some damage to it? Like if you’ve got a bathroom that has double sinks and they share sort of like a T-drain …
RICHARD: Yeah, it’s never – it’s not always as easy as I might make it sound or we make it seem on television. But typically, though, you’re going to run the snake down, it’s going to go in the right direction. And it’s worth looking at.
The bathtub is also a chronic stoppage point. And so, what you should look for – when you have a bathtub, people think, yeah, they have a drain stoppage. But most of these have a trip-lever device, which is the thing that lets you stop the drain to hold the water mechanically.
RICHARD: And behind that, that can often get clogged with hair and stuff. So, they think they have to run a snake down but what you really have to do is to pull that whole assembly out. If you were facing the overflow – that chrome thing that’s up on the side wall of the tub when you’re in the tub – there’s two screws there. Pull the screws out without dropping the screws into the drain and then pull that whole assembly out and you’ll be surprised what you can see in there, particularly if you’ve got people with long hair that can get down in the drain and …
LESLIE: Again, why is everybody looking at me? What’s going on?
RICHARD: Look, when you’re talking about hair, you don’t look at me.
TOM: We’re talking to Richard Trethewey, the plumbing-and-heating expert on TV’sThis Old House.
OK, so we’ve covered the mechanical clearing, the plungers and the hand snakes. What about the bigger snakes: the electronic drain cleaners when you have the really big pipes that are clogged?
RICHARD: Those are done by a professional and it’s the only way you can clear a main-drain stoppage. The main-drain stoppage in the American home is a very real problem.
What happens is we see, most often, the cause of it is tree roots . So when that sewer line goes out through the front foundation of the building, out to the street – if you see a nice, big, beautiful oak tree or some tree right next to it, there’s a good chance that little, tiny roots – little capillary roots off of the main roots – can get just into those connections. And once they get in there, they’re in a perfect place to grow because they get organic matter and warmth and water and they’ll keep on growing. And then you come in with a drain snake that’s got a nice cutter wheel at the end of it, you can then clean it and stuff but it’s still going to grow back.
So, people that live with this whole tree-in-the-front-yard stuff can live their lives worrying that in the next five years, they’re going to have to do it, you know, again and again. But it’s a real issue.
We did something on Ask This Old House that was a very interesting solution where we actually lined the existing pipe underneath the ground. This sort of inflatable sock that we sort of did like a clown’s balloon and inflated it down the entire length of the pipe that was covered with epoxy.
RICHARD: And the balloon – filled with water, at this point – held that sock until it cured. And it completely lined the inside of the pipe so that the roots could no longer get into it. It’s an amazing – so you’re not going to do it everywhere but you’re going to do it when you have a fancy landscape in the front yard where you really want to – wouldn’t want to dig up the front yard.
TOM: Yeah, it makes sense.
LESLIE: And I imagine that a drain camera was probably instrumental in that.
RICHARD: Oh, what – that technology is so cool now. Yeah, going down – “Here we go. Going down.”
RICHARD: Yeah. What’s nice is the homeowner can understand what the issue is.
LESLIE: The process.
RICHARD: Yeah, so they’re not sort of sitting in the dark, literally.
TOM: So the drain camera goes in the drain itself and you can actually see the physical leaks, see the root ball underneath the ground.
RICHARD: Yep. That’s right. That’s right. That’s right. Yeah.
Now, there’s one other thing I should mention that – we talked about chemical cleaners. They also have a really cool thing that I want to just mention. It’s an enzyme that once you put it down into the drain and it comes in contact with water and it’s got a little bit of warmth to it, these enzymes just start eating any organic matter.
And I’ve seen an example of this which, still, to this day – somebody put an entire can of it down into a cesspool. And it looked like it had been cleaned by a professional cleaning crew.
RICHARD: It’s just amazing. And this is a whole sort of natural, biological reaction versus a chemical. So, keep your eyes open for this whole enzyme biological cleaner.
TOM: Good advice. Richard Trethewey, the plumbing-and-heating expert on TV’s This Old House, thanks so much for stopping by The Money Pit.
RICHARD: Always great to see you guys.
LESLIE: You can catch the current season of This Old House and Ask This Old Houseon PBS. For local listings and step-by-step videos of many common home improvement projects, visit ThisOldHouse.com .
TOM: And you can watch This Old House and Ask This Old House on your local PBS station. Ask This Old House is brought to you by Angie’s List. Angie’s List, reviews you can trust.