Approved toilets include, but are not limited to, MaP Premium toilets. All MaP Premium labeled toilets have a flush volume of 4.0 litres or less and are WaterSense–certified. All WaterSense–certified and MaP Premium toilets are third party tested to ensure quality performance. For more information refer to map-testing.com and the High Efficiency and High Performance Toilets fact sheet.
Additionally, the WaterSense certification program provides rigorous third-party testing to ensure water-efficient products perform to a defined standard of quality.
Many local retailers carry 4.0 litre toilets. Talk to your local plumbing fixture supplier or plumber for more information.