Everything about MaP Toilet Flush Scores

While choosing a toilet, you need to choose the one that delivers maximum performance and water efficiency.

Checking the MaP rating of a toilet is the easiest way of knowing how efficient the toilet is. MaP is a standard score that represents how much solid waste product can a toilet remove per flush.

Besides, the EPA’s flushing standard is also maintained which is using 1.28 GPF or less water while flushing. This way, you’ll know that the toilet can remove all the waste from its bowl without wasting much water.

Let’s dive deep into the details and find out everything you need to know about MaP ratings.

What is a MaP Score?

The term MaP stands for Maximum Performance. In MaP testing, a particular toilet model is tested with a realistic medium to measure the amount of solid waste (in grams) removed in a single flush. The amount of water is also measured to rate the toilet based on its water efficiency.

A toilet can be rated anywhere from 250 to 1000 which indicates how many grams of waste a toilet can flush. In 2002, about 22 organizations in the United States and Canada came forward to start the MaP program for low-flow toilets. Any toilet that follows the EPA’s guideline of using 1.28 gallons of water per flush is called a low-flow toilet.

MaP is a voluntary test and the test results are made public. After its introduction in 2002, it soon became a reliable standard to rate toilet models. By now, around 5,000 toilet models have been tested using the MaP method.

So, in short, the MaP score of a toilet tells you the maximum amount of waste the toilet can remove pee flush.

What Are the Standards?

As mentioned, the MaP test is done to rate the performance and efficiency of a toilet. So, these are the standards followed while performing the MaP test. Below are the details-

Toilet Performance

In simple words, toilet performance refers to the capacity for waste removal. In general, average homeowners demand toilets that removes 150g of solid waste per flush. However, the Environmental Protection Agency (EPA) suggests a good toilet must remove 350g of solid waste in a single flush.

The MaP test is done using up to 1000g of solid waste. During the test, the toilet is rated depending on the maximum amount of waste the toilet can flush. For example, if a toilet flushes up to 400g of solid waste, the MaP rating for that toilet is 400.

Toilet Efficiency

It refers to the amount of water a toilet uses to completely remove solid waste from the toilet bowl. Nowadays, all toilets must follow the EPA’s standard flush rating of 1.28 GPF per flush. While it saves water, the low amount of water affects the toilet’s performance.

So, manufacturers use advanced technology to reduce water usage without compromising toilet performance. In fact, some MaP-certified toilets use only 0.8 gallons of water per flush.

Now, let’s take a look at the MaP standard scoring:

MaP Rating Flush Performance Recommendation

0g to 250g – Extremely Poor Performance Not Recommended

250g to 350g – Minimum Flush Performance Acceptable

350g to 600g – Strong Flush Performance Recommended

600g to 1000g – Great Flush Performance Highly Recommended

MaP Testing

To rate a toilet model, the MaP test is done by following an easy respectable method and realistic medium. A certain amount of soybean paste is used to replicate human waste. Here’s a short step-by-step process for doing the MaP test:

Step One: Preparing the Media

Typically, about 50g of soybean paste and toilet paper is mixed to prepare the test media. The mixture is given a ‘sausage’ shape. It’s about 100m long and has a 25mm diameter.

In standard laboratories, the mixture is put in a latex casing. A test specimen is then randomly selected. It weighs around 350g.

Step Two: Setting Up the Test Materials

The water level in the toilet tank should be as per the manufacturer’s recommendation. Water supply pressure should be around 50 PSIG. For the test, the recommended water temperature is 18 to 27°C or 65 to 80°F. Before conducting the test, each toilet is flushed at least three times.

After that, the flush volume is measured. As you might know, every toilet has a flush volume rate mentioned on its packaging. If the flush volume is 0.10 gallons greater than the rated flush volume, the fixture will be rejected.

Step Three: Waste Extraction Test

A drop guide is placed over the toilet bowl and the soybean paste is dropped freely into the bowl through the drop guide opening. The toilet is now flushed and the solid waste is collected with a suitable container for measurement.

To get the final MaP score, the test steps are repeated with more and more waste until the toilet fails to completely clean the bowl. The final measurements are noted and a toilet is rated depending on that result. While increasing the loading mass, the amount of waste never exceeds the standard 1000g limit.

What Is Flush-O-Meter?

Typically used in commercial toilets, a flush-o-meter is a water diverter that comes with a handle to flush commercial tankless toilets. A toilet that comes with a flush-o-meter is called a spud bowl and it uses the water pressure of the supply lines to clean the bowl.

This way, flush-o-meters save more water when compared to regular residential toilets with toilet tanks.

What are the Flush-O-Meter Commercial VS Residential Differences?

Now, you might wonder why flush-o-meters aren’t installed in residential toilets. That’s because there are some major differences between residential and flash-o-meter commercial toilets. Which includes-

Supply Line Size

To install a flush-o-meter commercial toilet, the supply lines must have a 1-inch diameter. Typically, most regular buildings have 1/2-inch supply lines. So, it’s not possible to install toilets with flush-o-meter valves in a regular house.

Besides, installing 1-inch supply pipes is way costlier than installing 1/2″ pipes. Hence, they are found only in newly made commercial buildings.


Without a doubt, flush-o-meter toilets are more water-efficient and high-performing. As they use water pressure instead of gravitational force, the flushing pressure is higher which cleans the bowl with less water.

What’re more, flush-o-meter valves work quickly and the mechanism is simpler.

Tank Size

Regular small or medium tanks used in residential areas aren’t suitable for installing flush-o-meter toilets. Larger tanks contain more water which provides sufficient pressure required for the flush-o-meter mechanism to work.

Again, larger tanks are costlier than small- and medium-sized tanks.

Loud Flushing Sound

Residential toilets with regular valves are quiet and have smooth functioning. On the other hand, flush-o-meter toilets are extremely loud. If you install these toilets in your house, your neighbors will hear a loud sound every time you flush.

This is another main reason why typical houses and apartment buildings in the US don’t use flush-o-meter toilets.

Wrapping Up!

So, that was everything you need to know about MaP. If a toilet has a MaP score between 500 and 1000, you can go for it for water efficiency and superior performance.

You can check the public database of the MaP test results to know what’s the score of your existing toilet. Finally, for commercial areas like stadiums and airports, toilets with a flush-o-meter valve are the most suitable choice.