What Is a MaP Score? Toilet Flush Testing Explained

The MaP (Maximum Performance) testing protocol was developed to give consumers and plumbers a reliable, repeatable way to compare toilet flush power. Unlike vague marketing claims like "power flush" or "tornado rinse," the MaP score is a specific number that tells you exactly how much material a toilet can move.

During testing, technicians load the toilet bowl with a measured amount of soybean paste (which has similar density and consistency to human waste) along with a specific number of toilet paper sheets. They flush and check whether all material clears the bowl and trapway. They repeat this process with increasing loads until the toilet fails to clear everything. The highest successful load is the MaP score.

For example, a toilet with a MaP score of 600g can reliably flush 600 grams of simulated waste plus toilet paper. A score of 1000g means it can handle over two pounds of material in a single flush. This standardized approach eliminates guesswork and gives homeowners a clear metric for choosing a toilet that won't clog.

Before MaP testing became common, toilet performance was a matter of marketing hype. Manufacturers would claim "powerful flushing" without any standard to back it up. Homeowners would install a new toilet only to find it clogged regularly. The MaP score changed that by providing a common benchmark that applies to all toilets regardless of brand or design.

When you shop for a toilet, the MaP score tells you how much waste the toilet can handle before it clogs. A score of 350g is the minimum for a toilet to meet basic performance standards, but many modern toilets exceed this significantly. Scores of 600g to 800g are common in well-designed toilets, and 1000g models represent the highest tested performance.

For households with multiple people, children who use too much toilet paper, or anyone who wants to minimize maintenance, a higher MaP score is a smart investment. It is especially important for toilets with lower water usage (1.28 GPF or 1.0 GPF) because less water means less force to move waste. A high MaP score confirms that the toilet compensates for reduced water volume with better bowl and trapway design.

Understanding what each score range means helps you choose the right toilet for your needs. The MaP testing program categorizes scores into practical tiers that reflect real-world performance. Here is how the ranges break down:

Most residential toilets sold today achieve at least 600g. The TOTO Drake is a popular model that typically scores 800g or higher, making it a reliable choice for families. The American Standard Champion 4 also scores well in this range and is known for its large trapway that resists clogs.

It is worth noting that MaP scores above 800g are not necessary for every household. A score of 600g is sufficient for most families, but if you have heavy usage or want the highest level of reliability, look for 800g or higher. The maximum tested score is 1000g, and toilets achieving this are typically commercial-grade or high-performance residential models.

The EPA WaterSense program requires toilets to use no more than 1.28 gallons per flush (GPF) while still passing a minimum performance test. However, WaterSense only requires a basic flush test, not the full MaP protocol. This means a WaterSense-certified toilet might meet the minimum standard but still have a mediocre MaP score.

High-efficiency toilets (HET) use 1.28 GPF or less, and some ultra-high-efficiency models use 1.0 GPF. These save significant water over older 1.6 GPF models, but they must be designed carefully to maintain flush performance. The best low-GPF toilets achieve MaP scores of 800g or higher, proving that water savings and reliable flushing can coexist.

When comparing toilets, look at both GPF and MaP score together. A 1.28 GPF toilet with a MaP score of 800g is an excellent choice. A 1.6 GPF toilet with a MaP score of 600g uses more water but flushes less effectively. The Kohler Highline is an example of a 1.28 GPF toilet that typically achieves a MaP score around 800g, offering both efficiency and performance.

Finding the MaP score for a toilet you are considering is straightforward. The MaP Testing program maintains a searchable database of tested toilets on their website. You can search by brand, model number, or score range to see how different toilets compare. This database is the most authoritative source for MaP scores.

Manufacturers also publish MaP scores in their product literature and on their websites. For example, TOTO lists MaP scores for many of their models, and American Standard includes them in specification sheets. When shopping online, check the product details or specification tab for MaP score information. If it is not listed, you can search the model number on the MaP website.

Some retailers and review sites also display MaP scores. However, always verify against the official MaP database because scores can vary between manufacturing runs or if the toilet design changes. The MaP score is tested on a specific model and configuration, so make sure you are looking at the exact model you plan to purchase.

The MaP score is a measure of flush power, but a toilet is a complex product with many features. Bowl shape (round vs. elongated), height (standard vs. comfort height), and rinse technology all affect user experience. A toilet that flushes well but has a poorly designed bowl that traps debris or a seat that is too low may not be ideal.

Additionally, MaP scores do not measure noise level, water spot size, or resistance to staining. Some toilets with powerful flushes are louder than others, and some have smaller water surfaces that require more frequent cleaning. These factors are subjective but important for daily use.

The best approach is to use MaP score as a key filter, then evaluate other features based on your preferences. For example, the TOTO Drake combines a high MaP score with a well-designed bowl and quiet operation, making it a top choice. But a toilet with a slightly lower MaP score might be better for you if it has a more comfortable seat or a more attractive design.

• EPA WaterSense, epa.gov/watersense
• MaP Flush Testing Program, map-testing.com
• Manufacturer published specifications