To determine the location of slow sand filters within the United States, individual state drinking water offices were contacted. A brief one page survey was then sent to all of the 224 slow sand filtration plants identified. The survey investigated the age of individual plant, average daily demand, total filter area, population served, pretreatment method, cleaning method, sand source and hours of operation per day. As of May 1995, 99 plants have returned the one page survey. The statistics presented in this paper are based on those 99 plants alone. A more detailed three-page survey was then sent to each of the 99 plants, and 45 plants have responded. Because the second survey was much more detailed and reflected the uniqueness of each individual plant, only general observations from the second survey are mentioned. This paper also discusses the cleaning methods used to remove the schmutzdecke of the slow sand filter. The response from the survey only reinforced the authors' opinion that there is a very wide range in the design of slow sand filters as well as the operation and maintenance strategies.