Reuben Saltzman

Podcast: Sewers and Floor Drains

We discuss all things related to wastewater leaving Minnesota houses, and how this relates to home inspections. We discuss the importance of sewer inspections on all houses, not just old houses, and discuss what it takes to fix these issues when they occur. We discuss the mystery of floor drains backing up, the importance of floor drain plugs, and how floor drains work. Here are some related blog post links:


The following is a transcription from an audio recording. Although the transcription is largely accurate, in some cases it may be slightly incomplete or contain minor inaccuracies due to inaudible passages or transcription errors.

Tessa Murry: One of the things we do when we’re inspecting houses is we fill up the tub with water and we let it drain to make sure that that drain is working, but also to make sure that we don’t have any issues with the main drain leaving the house. And we do that on every fixture, every sink we fill up, every tub we fill up, every toilet we flush. We put a ton of water down to check and make sure that it’s draining okay.


Bill Oelrich: On today’s program, we’re gonna talk about sewer drains, and where everything goes after you flush the toilet. Under no circumstance should any of this water ever come back into your home. We’re gonna run through some of the problems, some of the issues, and some of the materials that we see on a daily basis, and we’re gonna help you understand how your home is set up. One of the most popular topics we’ve ever had on our blog at Structure Tech is about floor drains. Reuben, what confuses people more than anything about their drains?


Reuben Saltzman: Well, Bill, number one, A1 with a bullet, is floor drains. Why floor drains back up? I wrote a blog post about this over 10 years ago. If you do a Google search, floor drain basics, that’s surely the first thing you’re gonna find. And it totally mystifies people why floor drains back up, and it’s not that confusing, but it’s a tough topic to understand. And the whole thing here is that a floor drain is the lowest plumbing fixture in your home. If you have a clog in your main building drain on the pipe that goes from your home out to the city, if you’ve got a clog there, and then you flush a toilet on the first floor, water is going to back up and it’s gonna come out of the lowest plumbing fixture. If your lowest plumbing fixture happens to be a sink, and you have no floor drain in your basement, you’re gonna have water that ends up backing up out of your sink, because the toilet is above it. If you happen to have a lower fixture, like a floor drain, you flush that toilet, and the water is backed up before it leaves your home, it’s going to leave at the lowest spot, and that’s gonna be the floor drain. And that’s why water comes out of them. There’s nothing super complicated about this, it’s just the lowest opening.


BO: Is that something you see on a regular basis? Tessa, have you ever run into it?


TM: Where water is backing up out of a floor drain? Yeah, I’ve seen that on inspections. One of the things we do when we’re inspecting houses is we fill up the tub with water, and we let it drain to make sure that that drain is working, but also to make sure that we don’t have any issues with the main drain leaving the house. And we do that on every fixture, every sink we fill up, every tub we fill up, every toilet we flush, we put a ton of water down to check and make sure that it’s draining okay.


RS: Yeah, we made that just a company policy, is you fill up bathtubs and then you go downstairs and you look at that floor drain, and either you check it out while the tub is draining or you come down there a half hour later and you make sure there’s not a big ring of water around that floor drain to make sure that you don’t have an issue with the main building drain. And short of doing a sewer inspection, that’s about the closest thing we can do during just a standard home inspection to make sure that there’s not an issue with the main building drain.


TM: Right. But I always tell people that are buying the house, you should probably consider doing a sewer inspection, because there’s no way that we can really fully inspect the sewer line. We’re putting a lot of water down it, but we have no idea what kinda condition it’s in, if there’s any breaks in the pipe, if there’s any sags or dips, tree roots. So the only way to know for sure is to do a sewer inspection.


RS: Yeah, but if there are problems, isn’t that the city’s responsibility?




TM: Great question. No, you own that sewer line. From your house to where it connects to the city sewer, that’s yours and that’s your responsibility to take care of. So if there’s an issue with it, that falls on you.


RS: Wow, okay, so the city is not gonna pay for that, but it’s not… Can’t be that expensive, right?


TM: Boy, [chuckle] I wish, right? We’ve been partnering with a company called Drain Busters here in the Twin Cities, and they do a lot of our sewer inspections, and I have seen so many failed sewer lines over the last three years that involve a dig to either replace pipe or correct another issue. And if that issue is located at the pipe that goes underneath the street, it is your responsibility to pay for digging up the street and then redoing the street.


RS: Yikes. Yikes. So, which houses do you recommend this on? ‘Cause, I used to be in the camp where I’d say, alright, if you’re buying a house, it’s got big trees right near the street, you could get roots in there, or if you’re buying a really old house with an old drain line, it’s a good idea to get a sewer inspection. But I’ve kinda changed my tune over the years. What about you?


TM: Same thing, Reuben, same thing. I recommend them on every single house. I personally would not buy a house without doing a sewer inspection.


RS: What if it’s like, 10 years old? You got a PVC drain line.


TM: Same thing. So, we found over the last few years, that there have been several newer homes that have had issues with their plastic PVC drain line.


RS: And what causes those issues?


TM: Well, Joe was talking about that. And some of those issues can be caused during construction. If they’ve got heavy machinery that’s driving over those pipes and the soil is not compacted yet, it can cause those pipes to have sags or dips or it can even damage the pipes as well. And I don’t know, are there any other issues you’ve heard of?


RS: Oh, and you know what? There’s one, I remember, Joe shared this video with us, where somebody was doing this jetting thing where they run a gas line under the ground, and they ran the gas line right through the sewer line.


TM: That’s crazy.


RS: And you know what, there was a whole that blew up because of that.


TM: Oh my gosh.


RS: It was a newer home and it was located right on… What was it? It was right on 50th Street, I think.


TM: Wow.


RS: And the house blew up, because they were doing this jetting and they ran a gas line through the sewer line, and then the sewer guy went in there, went to clean it out, tore the gas line open, and the house exploded.


TM: Wow. Oh my gosh.


RS: I’ve got pictures of it. You could drive by it right on 50th.


TM: Wow, wow. So just because it’s a new house doesn’t mean that it won’t have any issues and the only way to know for sure is to have that sewer inspection.


RS: Yeah, exactly. It’s cheap insurance. What do we charge for those now? It’s like, 200…


TM: 200-something.


RS: Yeah. Yeah. And when you think about… It’s standard procedure to test for radon if you’re buying a home today, but what does it cost to have a sewer inspection? It’s about the same thing.


TM: And, which is crazy, if you do have high radon, how much does it cost roughly to install a radon mitigation system?


RS: $1200, $1500.


TM: Now, how much would it cost to dig up your sewer line and replace it if it needs to be replaced?


RS: Oh, like 10 times that.




TM: Right. Wouldn’t you rather spend that money on maybe a sewer inspection?


RS: Yeah, if you’re just gonna get one thing, I would much rather get the sewer inspection.


TM: Me, too.


BO: So Reuben, besides backups, what else can go wrong with the floor drain?


RS: Biggest thing is a missing cleanout plug, and a floor drain is basically just a big old trap. Every plumbing fixture has a trap. It’s this dip in the pipe that prevents sewer gas from coming back into the home. Floor drains have that. Nobody gets to see the trap ’cause it’s buried under the ground, but there should always be water sitting in that floor drain to prevent sewer gas from coming in. But if you ever have a clog downstream from that floor drain, it’s really tough to get a sewer snake or a drain auger to go through that trap and then clean out the drain line going downstream. So most floor drains have what’s called a cleanout hole. It’s an actual hole on the side of the floor drain bowl that allows you to stick a drain auger in there. Now, if you have a clog downstream, you take out the cleanout plug, you stick a drain auger in there, you clean it out, and then the most important part, when you’re all done with that, you put the cleanout plug back in place. ‘Cause while that cleanout plug is removed, you’re gonna have sewer gas coming into your home, and it’s not gonna happen for very long, you put it all back together and you’re good. But it happens a lot in Minneapolis and St. Paul, older houses. We go downstairs, we’re walking down there, we smell sewer gas, and we go, “Oh, I know what’s going on here. There’s a missing cleanout plug somewhere.”


RS: So we’ll go find the floor drain, we’ll take a picture of it, we’ll say, “Put a cleanout plug in here,” but also, make sure the drain is functional. Because once you’ve pulled that plug, if there’s a clog at the trap underneath it, you don’t know it. The only way to know for sure is to replace that plug, and then make sure that it receives water. And my sister bought a home in St. Louis Park many years ago, and it had a missing cleanout plug. She got a repair order from the city of St. Louis Park. You gotta fix this. So you can guess who’s over there helping her fix all this. [chuckle] And I put that cleanout plug back in and I tried everything in my power to get that floor drain to work, and I could not get water to drain through it. I tried like a jack hammer, basically, to clean it out. Couldn’t get it to work. So I ended up having to replace the floor drain. And that’s a matter of taking a sledge hammer, breaking up all the concrete around the drain, getting a shovel, dig all the dirt out, get a Sawzall and cut the drain line off, install a new floor drain, replace the dirt, and pour new concrete.


BO: That’s not DIY.


TM: For Reuben, it is.


RS: Yeah. [chuckle] This is not your average homeowner project. This is like an all-day project for a plumber to replace a floor drain. It’s hideously expensive. And so, all of this was about the missing floor drain plug, cleanout plug. So, if you have a missing cleanout plug, watch out. It could be an expensive issue. It usually isn’t, but maybe one out of 10, it’s gonna be a big project.


BO: Reuben, do you have any resources you could provide for us that explain some of this in more detail?


RS: Well, I’ll tell you, about having sewer inspections on newer homes, we put together a compilation video showing all of these homes that we’ve looked at where it’s 10 years old or less, and we got terribly failed sewer lines. We’ve got a video compilation showing what a sewer inspection actually looks like from beginning to end. Lots of sped up, stop motion stuff, so the whole video is like two minutes. And we’ve got a lot of different blog posts about floor drains, cleanout plugs, why plumbing fixtures need traps, it’s all on the Structure Tech website at


BO: So Reuben and Tessa, we were talking about the main line and some of the problems that you can have going out to the street, which sound like a lot of money if you run into those kinds of problems, but what are the more inside the house problems that you see?


RS: Without a doubt, the most common thing that we find during home inspections is a slow drain in the master bathroom. And no offense, Tessa, but it’s always her side of the sink [chuckle] that’s… When you’ve got the double barrel sink. Whoever’s got the longer hair, that’s the one that tends to clog up faster. It’s an easy fix. That one, you get… The tool you’re referring to, it’s a… I think they call it a Zip It. It’s just this long piece of plastic with little barbs on there.


TM: Like little teeth on the side of it.


RS: Little… Yeah, yeah, and you just stick it down into the drain, you pull it out, and you’re gonna have this little hair mouse. It’s the most [chuckle] disgusting thing.




TM: So gross.




RS: It is.




TM: It’s so gross.


RS: But you could pull that hair ball out of there, and that’s usually all it takes in the bathroom. Now, if you have clogs elsewhere, maybe in the shower, maybe in the tub, could be the same thing, but the one to really look out for is a clog at the kitchen sink drain. Watch out for those. And I’m thinking about the kitchen sink drains for houses that have steel drain lines. It’s not so much an issue on the newer ones with the PVC pipes, ’cause there, you can stick a drain cleaner down here, you can use an auger, and side note, when I say, “drain cleaner,” I mean an auger. I mean a tool. Don’t use Drano.


BO: Why is that?


RS: It’ll basically melt your pipes. It’s an acid and it might work a couple of times, but for the most part, it’s gonna melt your pipes. Especially if you got steel pipes, it’ll eat through them.


BO: Okay, so no matter what material, it’s not good for any material?


RS: It is not.


BO: I’ve never heard that before.


RS: Yeah, I’ve heard plumbers talk about turning the PVC into like a plastic sludge. I don’t recommend any liquid products going down your drains.


TM: So Reuben, when we’re doing home inspections, one thing we’re looking for is galvanised steel drain pipes. And typically…


RS: Oh, sure.


TM: We’ll find that in houses that are, what, 1960s and before that?


RS: Exactly right.


TM: Yeah.


RS: Yeah.


TM: And those houses were definitely filling up kitchen sinks, both sides, if it’s got two sides to it, all the way and letting that water drain out to make sure that there isn’t a slow drain.


RS: ‘Cause sometimes, you can turn the faucet on, and water’s gonna drain down the sink just fine. It’ll keep up with the faucet for a while, but you fill both sides, you let it go, and sometimes, you’ll see that sink, it’ll drain quickly for a little while, and then all of a sudden, the water will just kinda slow down and then it’ll be still. And it’ll take another 20, 30 minutes for the rest of that water to drain out. And that’s an issue with the steel drain going all the way down into the basement, and it’s clogged, it’s corroded. And steel forms deposits on the inside and the diameter get smaller and smaller over time, and you can’t even bust that up with a drainage auger, or Drano, or anything else like that. The fix there is replace the drain line.


TM: Right. And same thing goes with water distribution pipes in the house if they’re galvanised steel. They can have the same issues where that diameter gets smaller and smaller. Any sort of galvanised steel drain pipe or water pipe that is still in use today is at the end of its expected serviceable life.


RS: Yes, yes it is.


BO: That’s interesting, because we actually saw that. We replaced the plumbing in our house. And we were doing the kitchen and I was just adding a new kitchen sink, and they were gonna redo some things. They cut the pipe about four feet off and my inch-and-a-half galvanised pipe had an inside diameter of less than a half an inch.


RS: Wow.




BO: It was like, “Wow. Okay.” So, you just keep cutting down the tree trunk till the bottom [chuckle] and then you build up with brand new. And that kitchen project led to replacing all the plumbing in the house, which was not inexpensive. [laughter] And every single fixture had the same concern. It was all corroded from the inside. And seeing is believing. I absolutely am so happy today we did this, because we would have been doing it five years from now, tearing up the new kitchen, the new bathroom, everything.


RS: And a lot of the time, as home inspectors, when we’re reporting on stuff being at the end of its life expectancy, a lot of times people confuse that with, “You must therefore replace this.” And I just wanna make it clear that when we’re saying that it’s at the end of its life, it doesn’t mean you have to do something about it today. It’s just, budget for this, right?


TM: Right. Your drain might be working just fine, your water flow might be just fine, but if you have these galvanised steel pipes, budget on replacing those at some point.


RS: Yeah.


BO: Is this the type of thing where you can splice into at any point and you go new to the old and it’s all good? Or say you have a slow drain here, can you just repair or replace or…


RS: When it’s unfinished spaces, it’s not that big of a deal. You can get couplers that will couple galvanised steel to modern PVC or ABS, and that’s no problem at all. You would replace as much of it as you practically could and typically, what you have is you’re gonna have a steel arm going from the kitchen sink over to the main stack, or down into the floor. And then down underneath the concrete floor, you’re never gonna have steel pipes there, ’cause those can’t be in contact with the concrete ’cause it’ll rust it out. But under the floor, you’re gonna have cast iron, and the cast iron’s fine. You really shouldn’t have anything to worry about there. So you replace as much of the steel as possible.


Clearly, it’s important that anybody in a real estate transaction consider a home inspection. It’s super important that you find a qualified home inspection expert to come out and do a thorough evaluation of the real estate you’re considering. Thanks for joining us. We’ll catch you next time.

You can also find our podcast on the following platforms:

Author: Reuben SaltzmanStructure Tech Home Inspections

Subscribe button