Seattle Home Inspector's Blog


The sounds of a healthy toilet


We all have experienced the toilet with a clogged drain that countered gravity---until it overflowed onto the floor.

Diving behind the toilet to get the water shut off as quickly as possible has happened to us all—especially if you have kids that are too young to deal with the crisis in any other way to scream.  I have never known screaming to help in the slightest—except in getting dad or mom on the scene pronto.

All plumbing drains rely on gravity to function.  This is a good use of gravity.  The quicker “out-of-sight-out-of-mind” the better, when it comes to the toilets function.  The rules of drain pipe installation are oriented toward assisting gravity as best we can.  The violation of these installation rules with improper piping, slope of pipes or types of fittings, can promote clogging and end up working against gravity.

This first picture shows a drain from a toilet that is flowing up hill.  Now we all know that under “normal” circumstances water doesn’t flow up hill, so what is really happening?

 Pipe from toilet sloping the wrong way

In this next picture I have done an overlay on the drain to show where there is going to be standing water in the pipe after the toilet has been flushed. 

water in the drain 

All of this water must be pushed out of the pipe every time the toilet is flushed and the toilet will not flush properly.  A shortcut taken by not calling a real plumber that understands the rules of gravity as well as plumbing pipe and fittings, has resulted in a toilet that does not flush properly. 

When you flush your toilet, it should make siphoning sounds consistent with good drainage. In other words--glug, glug, glug.


Charles Buell, Real Estate Inspections in Seattle

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Comment balloon 33 commentsCharles Buell • September 20 2013 06:28AM


Next time I use my toilet and will listen for the glug glug glug :-)  Thanks !

Posted by Kristin Johnston - REALTOR®, Giving Back With Each Home Sold! (RE/MAX Realty Center ) about 5 years ago

Hi Charles,

Not a good situation for the buyer or the seller.

I had one home last year that had the cast iron removed and the PVC installed. Only one problem.

Everything went up hill like in your shots.

Have a great day in the great Northwest my friend.

Best, Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) about 5 years ago

Charles:  Great explanation of the laws of nature .. and science!  Water issues ... plumbing issues ... ugh ...


Posted by Gene Mundt, IL/WI Mortgage Originator - FHA/VA/Conv/Jumbo/Portfolio/Refi, 708.921.6331 - 40+ yrs experience (NMLS #216987, IL Lic. 031.0006220, WI Licensed. APMC NMLS #175656) about 5 years ago

Oh, that can't be good.  We know somethings just won't flow uphill.  I bet they have a lot of toilet issues. Blah!

Posted by Mike Cooper, Your Winchester, VA Real Estate Sales Pro (Cornerstone Business Group Inc) about 5 years ago

I wonder if that's my problem with my shower drain. Obviously slightly different topic, but it always seems to drain really slow, even with pouring lots of draino and what not down there.

Posted by Suzanne Otto, Your Montgomery County PA home stager (Six Twenty Designs) about 5 years ago

Charles, Please remain seated while reading this comment, since getting up is also more difficult than sitting down. It not only has to do with gravity, but also weight.  Just imagine how hard it must be for flushing water to push a heavy load UP that pipe, over the peak and down the other side. I think you were being very polite by estimating the amount of water trapped in the pipe. ;-) I certainly wouldn't want to be the person doing a courtesy flush and hear the sound of glug, glug and then realize the toilet was PLUGGED. Thank you for sharing and explaining what could become a very messy situation. Best wishes always. 

Posted by Richard Yates, Broker and Realtor Orange County, California about 5 years ago

Kristin, yup---it should go glug, glug, glug :)

Clint, there is almost no excuse for this problem when changing to plastic because the piping takes up less space than the old cast iron

Gene, thanks

Mike, it will work over the short term but eventually it will lead to clogging of the drain

Suzanne, the shower drain should not go glug, glug, glug the same way a toilet does but it should drain properly.  It may not be possible to eliminate a clog with draino products and their could be venting and/or slope issues as well and size of drain issues.

Richard, there should never be standing water in the drain---except in the trap of course.  In the case of a toilet that would be just the water in the bowl.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago

Great illustration of the basics in Plumbing 101.  Here in South Florida most of our pipes are buried underground and the only way to see what you are showing is to snake a camera down the pipes.

Posted by Chuck Mixon, Cutler Bay Specialist, GRI, CDPE, BPOR (The Keyes Company) about 5 years ago

I will listen to ours on the next occassion to use them.  My Master toilet does not flush as well as the guest one so I am thinking I need to pay attention before I have to pay attention and get it fixed, by a professional!  Thanks for the lesson.

Posted by Evelyn Johnston, The People You Know, Like and Trust! (Friends & Neighbors Real Estate) about 5 years ago

Chuck, having drains scoped is a good idea---especially in homes built prior to the 60's

Evelyn, just keep in mind that some toilets will function just fine with only one glug instead of several glugs :)

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago

Charles: great post. We're nearing the end of our contest with over 115 entries to judge so far. Get ready! Take care.

Posted by Paul McFadden, Pest Control, Seattle, WA. (Paratex) about 5 years ago

Thanks for the good information.  I rrally don't want to hear the sound of a toilet that isn't flushing properly. That is not a good sound to hear.


Posted by Team Honeycutt (Allen Tate) about 5 years ago

Great post and use of images, Charles.  Wow, you mean even someone who isn't a plumber can't comprehend gravity?  What a sloppy job this contractor did.

Posted by Matt Kombrink, Your #1 Source For Real Estate (RE/MAX All Pro) about 5 years ago

Charles, some people just labor with common sense and that is a drain pipe just destined for a back-up

Posted by Ed Silva, Central CT Real Estate Broker Serving all equally (RE/MAX Professionals, CT 203-206-0754 ) about 5 years ago

I love your overlays... water, of course, can't go uphill.... until it does.  And the circumstances are typically messy when that happens.

Posted by Alan May, Helping you find your way home. (Coldwell Banker Residential) about 5 years ago

Funny, mine always go blooosh and then grlug grlug grlug. Must be my Illinois water supply. 

Posted by Scott Seaton Jr. Bourbonnais Kankakee IL Home Inspector, The Home Inspector With a Heart! (SLS Home Inspections-Bradley Bourbonnais Kankakee Manteno) about 5 years ago

Charles, trapped "water" in that drain line can never be a good thing. Thanks for the heads up.

Posted by Tom White, Franklin Homes Realty LLC, Franklin TN (Franklin Homes Realty LLC (615) 495-0752 or about 5 years ago

Doh!! Hey Charles what do you use to add the graphics to your photos?

Posted by Juan Jimenez, The Richmond Home Inspector (A House on a Rock Home Inspections LLC) about 5 years ago

Hi Charles, makes you wonder what they were thinking when they installed that piping.

Posted by Silvia Dukes PA, Broker Associate, CRS, CIPS, SRES, Florida Waterfront and Country Club Living (Tropic Shores Realty - Ich spreche Deutsch!) about 5 years ago

I just went over this with an elderly lady.  I explained what the problem was.

"But my son installed it it should be just fine.


Posted by William Feela, Realtor, Whispering Pines Realty 651-674-5999 No. (WHISPERING PINES REALTY) about 5 years ago

Paul, I will be ready :)

Betty, it will be interesting to see if they ever come up with a quiet toilet---besides the composting toilet :)

Matt, plumbing drains are all about gravity for sure

Ed, sooner or later

Alan, drains and sunamies are to be avoided at all costs :)

Scott, yes---mustn't for get what comes before the glug glug glug

Tom, you are welcome

Juan, excel, to pdf to photo capture/jpeg

Silvia, if every one was thinking enough I probably would not have a job

William, isn't every mother's son perfect?

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago

Hi Charlie... Oh yes, you are so correct about water and gravity and toilets... I have been there a few times, and a few of them complete with screaming kid and all! "Dad! Dad! Dad!"...

Posted by Rene Fabre, Marketing in the Digital Age (First American Title) about 5 years ago

Unreal.  I am not a plumbing expert but I would have to assume that angling a pipe the right way for water to run out is probably day one of plumbing 101.

Posted by Jay & Michelle Lieberman, Creating Calm in the Buying and Selling Chaos (Keller Williams World Class) about 5 years ago

Charles, I thought even elementary students were taught about gravity... wow. Great tip about the glug, glug, glug; I will surely keep listening out for that sound during each flush. Thanks.

Posted by Ralph Gorgoglione, Hawaii and California Real Estate (800) 591-6121 (Maui Life Homes / Metro Life Homes) about 5 years ago

If there is no water in the drain line under the bathroom then the pet alligator that got flushed will have no water to live in.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 5 years ago

Rene, I doubt that there is any parent that has not been there :)

Jay & Michelle, Uncle Harry missed the class entirely

Ralph, thanks

Jay, good point---gotta take care of the gators

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago

What a difference a few degrees can make Charles! It's important to keep that stuff flowing downhill.  :)

Posted by Tom Arstingstall, General Contractor, Dry Rot, Water Damage Sacramento, El Dorado County - (916) 765-5366, General Contractor, Dry Rot and Water Damage (Dry Rot and Water Damage Mobile - 916-765-5366) about 5 years ago

Good post...I had a plumber come over one day and he heard the glub glub glub and said you have good piping here. I never knew that sound meant that...but it does

Posted by Richie Alan Naggar, agent & author (people first...then business Ran Right Realty ) about 5 years ago

Tom, about "6 degrees of yuck":)

Richie, it is the sound of a healthy functioning toilet

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago

Chaarles, wow!  I always wanted to know what a good toilet sounds like - and what a releif to know that both of mine do glug!  And, I think one of the most important part of a home inspector's job is teaching my clients all about water cut-off valves!

Posted by Patricia Kennedy, Home in the Capital (RLAH Real Estate) about 5 years ago

Nothing better than a good solid "Whoosh" at the end... right?

Posted by Fred Hernden, CMI, Albuquerque area Master Inspector (Superior Home Inspections - Greater Albuquerque Area) about 5 years ago

Glug, glug, glug, three men in a...toilet??? 

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 5 years ago

Pat, yes, a water shut-off ins perhaps more important at a toilet than at other fixtures

Fred, yup---every toilet should easily flush the average cat with not problem :)

Jim, close enough

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 5 years ago