Bacteria are cosmopolitan, they are found in land, soil, air water, food, animals, plants etc. Many types of bacteria are found in human intenstine such as Eschrichia coli. They are found in temperature from -190°C to 78°C and some can survive in Ice and boiling water.
They are found in air up to height of many thousand feet and in thc Earth upto adepth of 16 feet, Bacteria are not found in rain water, distilled water, deep well water and volcano ash. They are abundantl found in faeces, milk products. fruits, vegetables etc.