A Sacrarium is a special basin that is connected by a pipe directly to the ground. Sacrariums are found inside Roman Catholic church buildings. The purpose of the Sacrarium is to dispose of water used sacramentally, and particles of the consecrated Eucharist by returning these particles directly to the earth from which it came.

Ordinarily the Sacrarium is used in cleaning the vessels used during the course of the Mass. Cleaning the vessels in this basin ensures that any remaining consecrated particles are returned directly to the Earth. However if consecrated hosts become unusable, the priest is to dispose of the hosts by placing them in the Sacrarium. This is accomplished by breaking the hosts up into small pieces and washing them into the basin - which returns the consecrated hosts to the ground.

At times the Sacrarium has been used for disposal of other items, such as old baptismal water, holy oils, and leftover ashes. In the past, consecrated wine was also poured down the Sacrarium. However in modern church practice such wine that is left over after communion is consumed either by the priest, or by the Eucharistic Ministers.