The New York City Tenement House Act of 1867 defined a tenement as any rented or leased dwelling that housed more than three independent families. Tenements were first built to accommodate the waves of immigrants arriving in the United States during the 1840s and 1850s, and until the 1930s they represented the primary form of urban working-class housing. From the beginning of their efforts, reformers attacked tenements for overcrowding; poor sanitation, such as overflowing privies; and lack of running water, proper sewage, and air and light. Between 1853 and 1917, AICP and COS were instrumental in publicizing and reforming the conditions of tenement housing through lectures, exhibitions, books, reports, journals, and pamphlets. Their actions resulted in the New York State Tenement House Act of 1901 and the creation of the New York City Tenement House Department.