Growth tiers for Anne Arundel County. In 2012, the Maryland General Assembly passed the Sustainable Growth and Agricultural Preservation Act of 2012 to address major developments served by on-site sewage disposal systems and their impact on the Chesapeake Bay and its tributaries. The legislation requires all local jurisdictions in Maryland to develop and adopt a system of Growth Tiers for future residential development. Four tiers were established to identify where major and minor residential subdivisions may be located in a jurisdiction and what type of sewerage system can serve them.