Pail closets, outhouses, and cesspits were used to collect human waste. Open sewers often ran through rooms and cesspits were left untended. These would take the form of backfilled wells and cesspits. Other breeding sites include&colon; natural marshes, cesspits, gutters, and other unkempt artificial water structures. Below ground archaeological remains could exist in the form of wells or cesspits. Municipal reforms required that cesspits be built of solid walls of stone and concrete. At the time there were cesspits under most homes. Cesspits are generally prohibited in developed areas. Some cesspits were still in use in Paris into the 20th century. Cesspits were cleaned out by tradesmen using shovels and horse-drawn wagons. In France, Germany, Spain and Switzerland, cesspits are forbidden. Cesspits contaminated the wells which many people still used to get their water. Cesspits were often placed under cellar floors or in the yard of a house. The back yard was also used for cesspits and for the disposal of rubbish.