Collection of sewage from toilets in a closed tank provides good protection for the environment and health. The closed tank reduces emissions of fertilizing substances, and other substances that may pose a risk, such as pathogens and drug residues. To reduce the water volume in the tank, it is advantageous to connect an extremely low-flush toilet, which means that the average flush volume is a maximum of 1 liter per flush. It is important that the toilet system is reliable for the technology to be used to a greater extent. This study examines experiences and functioning of extremely low-flush toilets to identify possible deficiencies and possible areas for improvement. Information has been obtained through telephone interviews and online surveys. The result shows that most respondents are generally satisfied with their extremely low-flush toilets. For the system to function optimally, it must be properly installed and maintained. There are some deficiencies that are more common, such as interruptions caused by flushing of incorrect objects or incorrect installation, but also some occasional errors. Many malfunctions appear to be caused by improper use or installation. There may be a need to develop certain technology components, such as the alarm function. The sound when flushing can be perceived as too loud. It is important that there are clear instructions for installation, maintenance, and use, as well as functioning service networks in case of problems.