How many bottles of liquid soap do you have in your house? The average American household has at least five plastic bottles of hand soap, body wash and shampoo. If you replace them every three months, you’ll go through about 20 plastic bottles each year. Many people have gotten used to the convenience of liquid soap, despite the high cost. Some think that bar soaps pass along germs. But a study from 1965 in which scientists conducted a series of experiments where they contaminated their hands with about five billion bacteria, such as Staph and E.coli and then washed with bar soap. When the next person used the soap, no germs were found on their hands.