This study aimed to objectively assess a long-term Assertive Community Treatment (ACT) programme run by a suburban mental health hospital in Western Australia. The study examined the programme by tracking Emergency Department (ED) presentations, hospital admissions and length of hospital stays (bed days) of people with severe mental illness who entered the programme. Between January 2008 - June 2019, 160 clients who attended the hospital had presentation and admission activities assessed at two time periods (1) PRE - the period from each client's first engagement with the mental health service up to their entering the service's ACT programme, and (2) DURING- which is the time that each client spent engaged in that ACT programme. No difference was found between ED presentations before the ACT programme as compared to during the ACT programme. Voluntary mental health hospital admissions were significantly lower during the programme than before the programme, but no difference was found for involuntary mental health hospital admissions. Both voluntary and involuntary hospital stays, however, showed a significant reduction in bed days for clients during their time in the ACT programme. This data shows the continued use of the ACT programme at suburban mental health services to be beneficial. While the number of ED presentations and involuntary admissions remained the same (although for different reasons), the reduction in voluntary hospital admissions and hospital bed days suggests that the increased provision of outpatient and home care through ACT is still working to support clients in the community keeping them out of more restrictive hospital settings.