The Washington State Department of Transportation municipal stormwater monitoring program, in operation for about 8 years, never has received an external, objective assessment. In addition, the Washington State Department of Transportation would like to identify the standard operating procedures and quality assurance protocols that must be adopted so that their monitoring program will meet the requirements of the new National Pollutant Discharge Elimination System municipal stormwater permit. As a result, in March 2009, the Washington State Department of Transportation asked the U.S. Geological Survey to assess their pre-2009 municipal stormwater monitoring program. This report presents guidelines developed for the Washington State Department of Transportation to meet new permit requirements and regional/national stormwater monitoring standards to ensure that adequate processes and procedures are identified to collect high-quality, scientifically defensible municipal stormwater monitoring data. These include: (1) development of coherent vision and cooperation among all elements of the program; (2) a comprehensive approach for site selection; (3) an effective quality assurance program for field, laboratory, and data management; and (4) an adequate database and data management system.