John Koeller
Koeller & Company
Office 714.777.2744
Mobile 714.757.0679
Bill Gauley
Gauley Associates, LTD.


15 Important Tips BEFORE You Purchase a Toilet

BEFORE you ever leave the house to shop for a toilet, get out your tape measure and gather the information you will need! Click on tips to view suggestions.

Download These 15 Important Tips


    Know the rough-in dimension of your toilet installation.  The distance from the flange bolts (that anchor your bowl to the floor, usually covered by small plastic caps) to the wall behind your toilet is known as the rough-in.  In most North American homes that dimension is either 10, 12, or 14 inches, the most common in today’s homes being 12 inches.


    The distance from the floor to the top rim of the bowl (not including the toilet seat).   In North America, that distance has traditionally been about 14 to 15 inches.  However, the trend for many families today is to install bowls with a height of 16 to 18 inches.  Manufacturers use terms such as “Comfort Height”, “Chair Height”, “Easy Height”, “Right Height”, “Highboy”, “Smart Height”, “ADA Height”, or some other similar description.  The added height makes getting on and off the bowl easier, especially for the elderly or infirm, but many younger persons have also discovered the benefits.  Decide whether or not you want a toilet with a taller bowl.


    Two-piece toilets are the most common design found in homes today.  They are typically less expensive and usually have a taller tank.  One-piece toilets, on the other hand, are generally more expensive but they are often easier to clean and may provide a smoother or sleeker appearance.  Decide on one-piece or two-piece.


    If you are replacing an existing toilet that has a large footprint (i.e., the base covers a large floor area), consider the patching and repair to the floor that might be required if a bowl with a smaller footprint is chosen.  This is especially an issue where ceramic tile covers the floor around the toilet.  Will additional matching tile be required and will the appearance be satisfactory?  Footprint dimensions of most new toilets may be found on the manufacturers’ websites.


    Again, if you are replacing an older toilet that has a large tank AND the wall area that is hidden behind that tank is unfinished or unpainted, consider that the installation of a smaller tank (typical of many of today’s toilet models) may leave those unpainted areas visible.  As such, you may be required to repaint a portion of the wall or even the entire bathroom.


    Choosing the bowl design is another important factor. Bowls are typically designed with either a smaller, round-front bowl or a longer, elongated-front bowl. The round-front bowl is ideal for compact bathroom spaces. Elongated bowls have a longer rim dimension (as much as 2 inches longer).  They are more comfortable for adult use and they help improved hygiene.  Be sure to measure the dimensions of your existing bowl and consider the size of the toilet space in your bathroom before replacing a round-front model with an elongated model.  There have been cases where doors and drawers could not be opened when the old round front bowl was replaced with an elongated model!  Check manufacturer websites for the dimensions of bowls and tanks. Decide on the bowl shape.


    Check the condition of your existing shut-off valve (called the ‘angle stop’) that supplies water to the toilet and the supply hose connecting that valve with your toilet tank.  If you need to replace the supply hose, consider one encased in stainless steel mesh for long-term durability.   If the shut-off valve needs replacing, it may be necessary to call your plumber.


    Manufacturers place flush handles at various locations on the tank:  right side, right front, left side, left front, and at the top-center of the tank lid.  You should determine if the handle’s location is important.


    Do you have a shelf installed directly above your toilet, such as the type occasionally found in older homes?  If so, be sure to measure the distance from the floor to that shelf.  Then consider that distance to be a limit upon the overall height of the combined bowl and tank you plan to purchase.  It is important to leave sufficient room between the tank lid and the shelf such that the lid can be removed and the parts inside the tank can be accessed when required.


    In certain climates (especially in humid climates and in buildings without air conditioning), sweating and dripping toilet tanks can be a problem.  As icy cold water refills the tank after a flush, condensation can form on the outside of the tank and drip on the floor.  This problem is far more common in older high flush volume toilets where the tank would totally empty and refill for each flush cycle.  Many new water efficient toilet models discharge only a portion of the water in the tank each flush, so the volume of cold water refilling the tank is less and the risk of condensation is far lower.  If you do have issues with condensation, there are two readily available solutions: choosing a pressure-assist model toilet OR choosing an insulated toilet tank. In a pressure-assist toilet, the water is contained within a separate pressure vessel inside the toilet tank; therefore, condensation does not form on the outside of the tank.  An insulated tank in a conventional gravity toilet (the type found in most homes) will keep that cold water from causing condensation on the outside of the tank. 

  11. MaP SCORE

     Of course, if you want a toilet with the best flush performance, you MUST check the MaP scores!  Go here to do a search for just the right toilet to meet your needs: Remember that toilets with scores of 500 and above will provide you with excellent performance.


    Gravity Fed: Fixtures that only use gravity (weight of the water in the tank) as the source of energy for flushing

    Pressure Assist: Fixtures that use the potential energy in the building's pressurized water line to compress air within a containment vessel inside the toilet tank. Compressed air behind the water provides a more vigorous flushing action than the gravity fed.

    Vacuum Assist - Fixtures that create a low level of vacuum (negative air pressure) to assist with the flushing action.


    Wall Mounted: Entire fixture is affixed to the wall and the entire weight of the bowl and tank are born by a carrier structure in the wall.

  14. COLOR

    Generally, a colored toilet can be a disadvantage, particularly if choosing a trendy color requires you to also replace the bathroom lavatory sink and the tub in order to maintain continuity.  In addition, when its time to sell your home, today’s ‘popular’ color may be tomorrow’s albatross.  We recommend sticking with white or off-white (sometimes referred to as biscuit or beige or bone), all of which are commonly found in homes today.

  15. COST

    Presumably the toilet you choose will be installed and operating for at least 20 years.  Don’t attempt to save a few dollars on a toilet purchase when you are making an ‘investment’ in your home that will have lasting functionality and use.  Also note that flush performance and user satisfaction is not directly related to what you paid for the toilet.  In fact, some of the best performing toilets are also the least expensive; and some of the most expensive are only marginal when it comes to performance.

Download These 15 Important Tips




Don’t fall for the salesman’s line “this toilet will flush 20 golf balls!” or “our toilet can flush a potato!”.  Neither of these claims (and others like them) have any relationship to the real world (unless, of course, you’ve decided to get rid of your stash of old golf balls!).  If you want to check the performance level of a toilet model, go to the MaP testing website.

Claims related to a “glazed trapway” only apply when a toilet is brand new.  In most instances, the trapway glazing provides no measurable benefits to flush performance after a year of use.





21st Century Toilet Performance Information, Free To Consumers

MaP is a Maximum Performance scale that rates toilet efficiency and flush performance, plus gives detailed information on individual toilet characteristics. The result is up-to-date, independently verified comprehensive toilet information in a SEARCHABLE database.

Search MaP Database

IMPORTANT:  MaP scores represent the number of grams of solid waste (soybean paste and toilet paper) that a particular toilet can flush and remove completely from the fixture in a SINGLE FLUSH.

History of MaP Toilet Testing

MaP was developed in 2002-03 in response to the many complaints of the 1990s about the new “low-flow” toilets (which, by the way, flushed with 1.6 gallons of water, less than 50% of the water used in its predecessors of the 1980s!).  MaP development was sponsored by members of the municipal water utility industry.  For more information on the background of MaP over the past two decades, click here.

While many toilet performance tests have existed for years (for example, manufacturers tests, Consumer Reports, and plumbing codes), ONLY MaP offers consumers the test results from closely replicating 'REAL WORLD' demands put upon a toilet.  MaP testing was initiated specifically to identify how well popular models performed using realistic test media (fecal simulation).

Testing Procedures

MaP incorporates the use of soybean paste and toilet paper to duplicate the 'real world' demands put upon toilets.  Each toilet is tested to FAILURE - - that is, soybean paste is repeatedly added to the toilet until the fixture can no longer remove it in a single flush.  Since 2003, over 4,000 different tank-type toilet models have been tested in this way and the results reported in the MaP online database.  Today, 4,304 tank-type toilet models are listed in today's MaP 'searchable' database.  Another 569 commercial flushometer valve/bowl combinations have also been MaP tested and reported.  In all cases, WaterSense-compliant tank-type and flushometer valve/bowl combination toilets are shown.