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Tiers Map


The Maryland General Assembly approved the Sustainable Growth & Agricultural Preservation Act of 2012 (Senate Bill 236), also known as the septics bill, during the 2012 General Assembly session.
SB 236 requires local jurisdictions to establish and adopt growth tiers to control the number of new subdivisions on septic fields.  The purpose of the bill is to protect agriculture, control growth in rural areas, promote growth in areas that have infrastructure in place for it, and reduce nitrogen from septic systems, a primary pollutant of the Chesapeake Bay.

The Montgomery County Council has amended our subdivision regulations to comply with the new law.   Planning Department staff have prepared a Growth Tiers Map a Subdivision Regulation Amendment to incorporate the Map.

Growth Tiers Map

The Growth Tiers Map shows the location of the four Tiers in the County.

  • Tier I: Areas currently served by sewer
  • Tier II: Future Growth Areas planned for sewer
  • Tier III: Large Lot Development and “Rural Villages” on septic systems
  • Tier IV: Preservation and Conservation Areas. No Major subdivisions on septics except by exemption Montgomery County has been approved by the Maryland Department of Planning to allow major subdivisions on septic systems.

The County has received certification from the State so that major subdivisions on septic systems in Tier IV will be allowed.  The County’s Agricultural Reserve will continue to protect agriculture and limit development in the County’s rural areas through Transfer of Development Rights and very low density residential development.

For further information on SB 236 see the Maryland Department of Planning’s SB 236 webpage.


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Subdivision Approvals Allowed in Each Growth Tier in Montgomery County

Tier I Tier II Tier III Tier IV
Minor Subdivisions on Septic Systems NO YES YES YES
Minor Subdivisions on Sewer YES YES YES YES
Major Subdivisions on Septic Systems NO NO YES YES
Major Subdivisions on Sewer YES YES YES YES
Last Updated: July 1, 2022