The project is about saving potable water in households and public facilities by installing: water saving showers and wash basins with aerators and sprinklers, which use smaller amounts of water and locks massive water stream. Toilets with 2 flushing water volumes; the classic water flushing toilet has a volume of 8-12 liters, but to flush after a slash doesn't require a big volume as only 3-4,5 liters are needed. By installing toilets with 2 flushing volumes – a small volume of 3-4,5 liters and a big volume 6-9 liters a big amount of potable water can be saved. In general, 1 person visits the toilet 1 time daily for pooping and 3 times for slash. By using classic toilet cisterns with 12 liter volumes, the daily amount will be 4*12=48 liters/day/person.
By using a WC with 2 flushing water volumes; 4 liters and 8 liters, the used water amount will be 1*8+3*4=20 liters per day per person, which is 28 liters less and will save 58% of potable water.
By using such WC in public facilities the saved potable water will be multiplied, as well as it may save 50-60% of water, as 28 liters/person/day times 7,5 million people in Bulgaria = 210 000 m3/day saved potable water.