DEAR TIM: I am looking at toilets for my new bathroom. Our current toilet measures 23 inches from the back wall to the front edge of where the toilet touches the floor. Many of the measurements in brochures seem to start at nearly 27 inches. Space is valuable in this small room. We also have a flushing problem with our current toilet. It seems to always require two or three flushes to rid the bowl of waste. Karen N., Williamstown, NJ

DEAR KAREN: I don't think you are comparing apples to apples. You measured the foot extension of the toilet. The foot is the actual surface dimension and shape of where the toilet bowl base contacts the floor. Bathroom planners and plumbers are rarely interested in that dimension. The most critical dimension is the distance from the front of the bowl where the toilet seat contacts the china bowl to the back of the toilet. My guess is that if you measure your existing toilet, you will quickly discover it extends 27 or even 28 inches from the back wall.

An often overlooked measurement is the rough-in dimension of the toilet bowl. This measurement is the distance from the back of the toilet to the center of the waste outlet hole on the underside of the toilet bowl. The most common dimension is 12 inches. But many toilet manufacturers also offer two other sizes in case mistakes are made during construction or a pesky floor joist gets in the way. It is not unusual to find toilets with a 10 or 14 inch rough-in dimension. Be sure you purchase a toilet bowl that has the correct rough-in dimension to match your current drainage pipe location.

Toilet technology has made significant advancements in the past seven to ten years. In fact, certain manufacturers continue to devote significant research and development resources to toilet design and functionality. There are millions of consumers who are disappointed with the performance of toilets since the low flush water savings law was enacted in January of 1994. You are a perfect example of how that law has backfired. The intent was for toilets to save water by using less water per flush. But if you flush twice or even three times, you may end up using even more water than with an older 3.5 or 5 gallon per flush model.

Flushing toilets is all about physics and stored potential energy. The water that is at rest in the tank just before the flush has the ability to do work because of its weight and the pull of gravity once the flush handle is activated. For the flush to be complete, this water needs to enter the bowl as rapidly as possible and encounter as little friction as possible as it leaves the bowl on its way to the drain. You can buy toilets that have enormous three and one-quarter inch flush valve openings at the bottom of the tank. These same toilets have fully-glazed trapways so the water and waste slips through the toilet with minimal friction.

Certain toilets are so well-engineered they can flush solid waste with just 1.4 gallons of water per flush instead of the industry standard of 1.6 gallons of water. This small savings per flush can add up to big savings over time. A family of four using one of these toilets can save nearly 2,000 gallons of water per year. Imagine how much water could be saved if an entire subdivision or city used these toilets.

The advancements in toilet design do not stop at the toilet bowl. You or your plumber can now buy new toilets that take the hassle out of connecting the tank to the toilet bowl. In years past, I and many others struggled with bolts and washers that passed through holes in the bottom of the tank. Tighten the bolts too much and you risk cracking the china. If the bolts were not tightened enough water would leak through the bottom of the bowl.

A new tank design eliminates these holes by using a hidden steel plate on the underside of the tank. The bolts lock into the steel plate and then pass through the holes in the back of the toilet bowl. It is an ingenious concept that will save both time in installation and service calls created by leaks.

Click here to watch a video on how a toilet works.

Received April 12, 2004:

"This is the first column I have read by anyone that so correctly details how the 1.6 gallon toilets work. My company has installed over 60,000 low flow 1.6 GPF toilets in the Tampa Bay area with virtually no trouble. In fact, the only problem we have is with competing plumbers who say ' ...those new toilets don't work!' Thanks for setting the record straight." Lou Bernucca

Author's Note: Thanks Lou! I am humbled to get praise from a fellow licensed plumber. TC

Low quality toilets can have a hidden defect that is often very hard to see. Toilets have a colon inside of them that is simply the path of the trapway. The trapway is the internal sealed tube that connects the bowl with the drain exit hole at the base of the toilet. It serves the same purpose as the trap drains one sees under a standard kitchen or bathroom sink. This colon used to be hidden on many older toilets but it is now common to actually see the convoluted pathway the water and waste takes as it travels from the bowl to the drain hole in the floor.

Toilets that are hard to flush or that clog on a frequent basis may be the victims of poor colon design. You can clearly see the colon of a toilet in the above photograph. The bends within the colon may be too tight. The actual interior size of the colon may be small. Try to buy toilets that have a two inch minimum trapway/colon or those that have even large diameter colons. Ask the plumbing supply sales person to show you different toilets with exposed colons so you can see how some have better streamlining than others.

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Comments: Welcome! I, Tim Carter, don't answer questions here. If you post a question here in the Comments Area, perhaps another visitor will help you. You need to go to the Ask Tim page if you want a question answered. Once there, look closely at how many weeks behind we are. Please be patient as you use this free service. If you have an emergency and need to talk to me, there is an option there for you. Aaron Witt 25 Nov 2007, 20:09 I have had a lic. plumber install my low flow elongated toilet and other plumbing. since then I have nothing but problems, ( other references say he is just not very good ), The most frustrating is the new toilet bubbles excitedly from the syphon just when flushed. is their a vent which may be plugged for the syphon jet? how would I fix this? american standard 1.6lpf. very frustrated. ATB 26 Nov 2007, 06:10 Aaron, Test to make sure the toilet and drain line are free of clogs. Pour a 5-gallon bucket of water into the bowl as fast as you possibly can. If the water is consumed with no overflow, this tells you the design of the toilet might be flawed. I have a Kohler low flow that works magnificently. Julie Maidment 02 Jan 2008, 21:42 There is a drip into my sewer pipe from the toilet...? The reason for the question mark is: Our plumber came today to investigate this. He drained all the water from the toilet and tank. He prevented any faucet leaks from going down the drain. I was down next to the sewer pipe in a crawl space below the bathroom (old house)and though the drip decreased, it did not cease. He cannon figure out where the drip is coming from. Any ideas? AsktheBuilder 03 Jan 2008, 07:50 Julie, It could be condensation in the vent portion of the system. It could be water draining from biofilm on the sides of the pipes, etc. May I ask why this is a concern? If the drain pipes have no leaks, what does it matter that water is in the pipes? Steve Ott 03 Feb 2008, 17:44 Tim, I need to replace the original 1952 American Standard toilet in my bathroom, since the bowl is cracked. I've removed the toilet and noted that I have a cast iron drain pipe with an I.D. of around 3 3/4" (I assume this is referred to as a 4" pipe). If I install a modern toilet with only a 1.6 gal flush rate, will it work effectively with my current waste pipe? I have heard there can be problems due to not enough water volume to carry away the waste. Also, would you recommend any particular type and brand of toilet? Thanks! AsktheBuilder 04 Feb 2008, 05:54 Steve, If the drain piping was installed with the proper slope, there should not be a problem. Let price be your road map. Toilets that flush well the first time cost more than the bargain big box toilets. Candy Sheehan 14 Mar 2008, 20:52 Hi there, boy I hope you can help me, I am about to give up. I need a toilet with a 10" rough in and is no more than 27" high as it has to fit under an existing small marble counter top extension. My old toilet fit nicely (townhome built in 1988) but my plumber and I have been unable to locate any new toilet that will work. That plugged hole in the floor is getting real old! Candy Carey Hanlin 05 May 2008, 14:30 Hello Steve Ott, My mom has a 1952 Standard toilet in her house. My brother broke the tank trying to reattach it. I am having huge difficulties finding one. Would you be willing to help me out? Thank you, Carey Hanlin Sasha 16 May 2008, 12:01 Thanks so much for the tips Tim! I have been in the market for a toilet for awhile and finally decided on a <a href="http://www.buyplumbing.net/toto.html">Toto</A> toilet. It is absolutely amazing. I love it! Thanks so much for your articles and help! Greatly appreciated! jdelay 07 Jul 2008, 19:27 I need a toilet with a rough-in less than 10 inches. Does such exist? If so, where? I would like to put the toilet in my camper and the rough-in is about nine inches. Thanks.      View all comments *Name: Email: Notify me about new comments on this page Hide my email *Text: Security Image: Security Image Text:   Remember, Tim Carter doesn't answer questions here in the comments. You need to go to the Ask Tim page.