services. Other multi-utilities provide power and water services, but no sewer services, such as the Los Angeles Department of Water and Power and the Orlando Utilities Commission. There are also some utilities that provide only sewer services, such as the Metropolitan Water Reclamation District of Greater Chicago or the sewer utility in the city of Santa Clara. Bulk water suppliers. There are also a few large bulk water suppliers in the arid Southwest of the United States, which sell water to utilities. The Metropolitan Water District of Southern California (MWD) sells treated water from the Colorado River and Northern California to its member utilities in Southern California through the California Aqueduct. Twenty-six cities and water districts serving 18 million people are members of MWD. The Central Arizona Water Conservation district supplies water from the Colorado River to 80 municipal, industrial, agricultural and Indian customers in Central and Southern Arizona through the Central Arizona Project Aqueduct (CAP). Regulators The economic regulation of water and sanitation service providers in the U.S. (in particular in relation to the setting of user water rates) is usually the responsibility of regulators such as Public Utility Commissions at the state level, which are organized in the National Association of Regulatory Utility Commissioners. (see economic regulator). However, while all investor-owned utilities are subject to tariff regulation, only few public utilities are subjected to the same regulation. In fact, only 12 states have laws restricting pricing practices by public water and sanitation utilities. The environmental and drinking water quality regulation is the responsibility of state departments of health or environment and the EPA. The Resource Conservation and Recovery Act (RCRA), protects groundwater by regulating the disposal of solid waste and hazardous waste. The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as "Superfund," requires remediation of abandoned hazardous waste sites. Wastewater treatment The United States Environmental Protection Agency (EPA) and state environmental agencies set wastewater standards under the Clean Water Act. Point sources must obtain surface water discharge permits through the National Pollutant Discharge Elimination System (NPDES). Point sources include industrial facilities, municipal governments (sewage treatment plants and storm sewer systems), other government facilities such as military bases, and some agricultural facilities, such as animal feedlots. EPA sets basic national wastewater standards: The "Secondary Treatment Regulation" applies to municipal sewage treatment plants, and the "Effluent guidelines" which are regulations for categories of industrial facilities. These standards