U.S. drinking water and wastewater systems encompass thousands of treatment and collection facilities and more than a million miles of pipes and conduits. The estimated cost to repair, replace, or upgrade aging facilities; accommodate the nation's growing population; and meet new water quality standards ranges from $300 billion to $1 trillion over the next 20 years. Although user rates are the major source of facilities' financing, federal and state government agencies also offer financial support. From fiscal years 1991 through 2000, nine federal agencies provided $44 billion for drinking water and wastewater capital improvements. Four agencies--the Environmental Protection Agency and the Departments of Agriculture, Housing and Urban Development, and Commerce--accounted for about 98 percent of that account. State governments made $25 billion available for water infrastructure programs during the past 10 years.