Rating System for Water Efficient Toilets

Article updated November 11, 2019 Did you know there is a rating system for toilets called the Maximum Performance test (MaP testing)? It tests how effective toilets are at flushing waste. The concept developed out of a group of 22 municipalities and regions from across Canada and the United States. The Maximum Performance test group coordinates the independent third party testing of toilets on the basis of their effectiveness at flushing waste. The group has  a website devoted to helping you learn about which toilets have been tested and rated for their flush performance.  This is a handy reference tool for people who’ve had a negative experience with low-flush toilets in the past. It can help you choose a low-flow toilet with maximum flush capability. The MaP website evaluates over 4000 residential toilets on their effectiveness at flushing waste in a single flush.  Any manufacturer can send their toilet to an independent testing centre to have its MaP measured.

What is a toilet’s maximum performance?

According to the MaP test website, toilets that are tested for their maximum performance are “tested to the point of failure.” What this means is that they keep adding more waste and flush until the quantity cannot be flushed with one flush; in other words – the maximum amount of waste. The minimum waste threshold of 350g is because that is the maximum amount that 99% of  human males will deposit in one sitting. If you want a more detailed explanation – visit the FAQ section of the MaP test website. Suffice it to say, you want a toilet that at least meets the 350g standard.

WaterSense vs. MaP tested toilets

WaterSense is the certification that is developed by the US Environmental Protection Agency as a standard to reduce toilets’ water use. However, not all toilets are  WaterSense certified and not all toilets are MaP tested. Better yet, some WaterSense toilets are not MaP tested and  some MaP tested toilets are not WaterSense….Are you still with me? That being said, ALL WaterSense toilets MUST meet the minimum MaP requirement of 350g. So, if you find a WaterSense certified toilet, it means that it uses a maximum of 4.8L (1.28 gallons) per flush, and will flush a sufficient amount of waste. BUT there are many models that are BOTH WaterSense certified and MaP tested and the website recommends that you select a toilet with a MaP rating of 600 or more. This brochure has some great tips on choosing a toilet.

MaP Premium

In a recent development, the MaP test group has introduced the MaP premium group of toilets – those which are both water efficient and flush effective. To qualify to be MaP premium a toilet MUST be WaterSense certified, have a water flush volume of no more than 4 litres (1.1 gallons) and a MaP rating of 600. Visit this page for more information and a list of toilet models that qualify. The MaP test website is a great way to see if toilets you are thinking about purchasing have all the qualities you are looking for. You can search and add any number of filters such as whether the toilet passes the American Disabilities Act criteria, has an elongated bowl, is one piece or two… You can compare one toilet to another as well so you can keep track of which ones you are thinking of. There is a section on whether toilets are pressure-assisted or gravity-based. According to their website, pressure-assist technology has come a long way since it was first introduced –  the majority of these types of toilets are now being installed in homes. (If you’re not familiar with pressure-assist toilets, a common complaint used to be that they were very loud.) I have a wishlist for the website that would make it even more useful than it already is:

1. Photos of toilet styles. The search results don’t pull up photos of the toilets — just the necessary information. While you might not think that toilet style is important to you, it’s probably more significant than you realize. The height of the toilet, where the flush handle is and the style of toilet in general are all factors to consider when replacing a toilet or building a new bathroom. So, it means you need to do a bit more homework – search out the model numbers of your ideal functional attributes on the website and then look them up at plumbing stores. This includes pricing information as well.
2. Pricing. In a perfect world a pricing scale would be listed along side each toilet and MaP rating (beside the picture and where the toilets are available for purchase ).
3. Noise rating. According to their FAQ section, although toilet flushing can be relatively loud depending on the toilet, it is not considered one of the priorities for people purchasing a toilet – and for labs to add the extra equipment to measure noise levels would be too costly to warrant the effort.

However, when you are in the market for a new toilet – go to this website to find effective flushing toilets which are also water efficient. Check out our toilet articles for more information on water efficient toilets.

• The Sydney Smart Point 8
• The SSi No Clog Toilet
• Beyond the 6 liter toilet

Feature photo – the SSi no clog toilet