Organic soils shall be grouped according to the following criteria:
Group A- Soils that have muck 51 inches deep or deeper, have adequate drainage and 10-year or better flood protection.
Group B- Soils that have muck 16 inches to 51 inches deep, at least 10 year flood protection and adequate drainage.
Group C- Soils that have muck 51 inches deep or deeper, are either subject to flooding one year out of five years or are inadequately drained, but not both.
Group D- Soils that have muck 16 inches to 51 inches deep, are subject to flooding once in five years and/or are inadequately drained, or are 51 inches deep or deeper and are both inadequately drained and floods once in five years.
N.Y. Comp. Codes R. & Regs. Tit. 1 § 370.7