Previous studies have shown that the water exchange method is associated with a significant reduction in discomfort and often allows patients to receive colonoscopy without sedation or with only minimal sedation. However, the potential for water exchange to be used in the screening setting has yet to be evaluated. As per standard practices in sigmoidoscopy screening, patients will not be sedated. However, unlike standard practices in sigmoidoscopy screening, while maintaining minimal levels of discomfort, the investigators will attempt to scope beyond the distal colon.