Importance . Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in K-12 settings . Objectives . To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for K-12 in-person learning . Design, Setting, and Participants . The pilot program engaged three schools for weekly saliva PCR testing of staff and students participating in in-person learning over a 5-week period . Wastewater, air, and surface samples were collected weekly and tested for SARS-CoV-2 RNA to determine surrogacy for case detection and interrogate transmission risk of in-building activities . Main Outcomes and Measures . SARS-CoV-2 detection in saliva and environmental samples and risk factors for SARS-CoV-2 infection . Results . 2,885 supervised self-collected saliva samples were tested from 773 asymptomatic staff and students during November and December , 2020 . 46 cases (22 students , 24 staff) were detected, representing a 5.8- and 2.5-fold increase in case detection rates among students and staff, respectively, compared to conventional reporting mechanisms . SARS-CoV-2 RNA was detected in wastewater samples from all pilot schools, as well as in air samples collected from two choir rooms . Sequencing of 21 viral genomes in saliva specimens demonstrated minimal clustering associated with one school . Geographic analysis of SARS-CoV-2 cases reported district-wide demonstrated higher community risk in zip codes proximal to the pilot schools . Conclusions and Relevance . Weekly screening of asymptomatic staff and students by saliva PCR testing dramatically increased SARS-CoV-2 case detection in an urban public-school setting, exceeding infection rates reported at the county level . Experiences differed among schools, and virus sequencing and geographic analyses suggest a dynamic interplay of school-based and community-derived transmission risk . Environmental testing for SARS-CoV-2 RNA in air and surface samples enabled real-time risk assessment of in-school activities and allowed for interventions in choir classes . Wastewater testing demonstrated the utility of school building-level SARS-CoV-2 surveillance . Collectively, these findings provide insight into the performance and community value of test-based SARS-CoV-2 screening and surveillance strategies in the K-12 educational setting.