If reports are to be believed, perhaps 20 million digesters— almost all of them underground masonry digesters— have been built in China, and many millions have been built in India and other countries as well. Depending primarily on the size of the digester and local prices for bricks (etc.), such a unit may cost from US$350 to US$500 and up, which is a great deal of money for a village family in most of the world.