Choosing Your Service Call Toilet

4 ways to ensure you won’t get a plumbing callback.
Choosing Your Service Call Toilet
Ed Del Grande

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Many of today’s homeowners wanting a new toilet installed do some research before calling a plumber. This can lead to the homeowner choosing the make and model of the toilet that will be installed. From a plumber's point of view this can be a good thing, since the choice and performance of the toilet is now on the client’s shoulders.

However, when on emergency calls or situations where a toilet unexpectedly needs to be changed, the choice of the new toilet is often made by the plumber. This is why most plumbers I know usually have a “go-to” toilet choice that they keep in stock or have quick access to at the local supply house.

While this is a good idea, when the responsibility of the toilet choice is on the plumber, we need to make sure the toilet performs up to high flushing standards. No plumber wants to have a callback due to poor toilet performance. With more toilets in today’s market and with high-efficiency toilets using less and less water, choosing carefully is very important.

If you are looking to stock a go-to toilet in your shop or truck, I recommend doing some performance research for your toilet of choice. Over the years I have had opportunities to work with toilet designers and learned some basic flushing tests they do on new toilets to help determine flushing power and bowl rinse. I’d like to share some of that information with you.

While most plumbers won’t have access to a toilet testing lab, we can still keep in mind how testing is conducted and what to look for when choosing a toilet that we recommend to our customers.

Here are four flushing tests I have performed with toilet designers, along with toilet features you should look for relating to these tests. While many new toilets may pass a few of these tests, a top-performing toilet may consistently pass all of these tests:

1. Bulk flushing test: Bulk flushing is when a toilet is loaded with heavy solids. Usually more than what may be encountered with normal in-the-field use. With bulk flushing toilets, the majority of the flushing water flows directly and quickly into the trapway to remove the solids. Look for toilets with large trap openings and “lazy bend” trap designs. A lazy bend trap is just a trap with less restrictive bends. With exposed trap toilets you can visually check for this design characteristic.

2. Full bowl rinse test: With less water per flush being used, getting enough water to completely rinse the entire bowl can be a challenge. Look for flushing systems that divert a good portion of the flushing water evenly through the bowl rim. This can help ensure a full washdown of the bowl. If you place small pieces of toilet paper around the upper part of the toilet bowl then flush, you can determine if the bowl is getting a full rinse. A timed rinse following the trap water can also aid with flushing power, as well as rinsing. Toilets that cannot deliver a complete bowl rinse may result in callbacks or complaints from customers. 

3. Light matter flushing test: Light matter is the stuff that floats on the bowl’s water spot. This can be some of the toughest matter to flush because it’s washed down at the end of the flushing cycle when less flushing power is available. The key to light waste removal is to look for a toilet that more or less empties the bowl every time the toilet is flushed. To test for light matter flushing you can simply sprinkle a little pepper over the water spot and observe how the toilet flushes away the pepper. A little pepper left behind is normal.

4. Paper flushing test: Using too much toilet paper is a big reason toilets can plug up. While you do need a bulk flushing system that can overcome an overload situation, when flushing toilet paper a “glazed” trapway can be just as important. A glazed trapway is when the inside channel of the trap is glazed and finished like the exposed areas of the bowl and toilet. This creates a very slippery channel to help the paper easily slide through the entire trapway. To check if a toilet has a fully glazed trapway see the manufacturer’s specs for confirmation of this feature.

My final bit of advice: For fewer callbacks with your toilet installs, work like a good plumber, but choose the toilets you install like a good engineer.

For more information, please visit and click on Ed’s Bonus Banner to see the companion video below: 

About the Author: Ed Del Grande is a three-time master plumber, GBCI LEED green associate and contractor with licenses in pipe fitting, fire protection and plumbing. He grew up in a family-owned plumbing business and has 30-plus years of construction experience.

A self-employed contractor and professional comedian, he combined his performing and construction talents to become a pioneer in home-improvement television. Starting on HGTV with shows such as Dream Builders and The Fix, Del Grande helped build the DIY Network and with shows such as Warehouse Warriors and Ed The Plumber


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