Actuarial rates for flood insurance - As used here the word "actuarial" refers to the rate that would be charged a similar property that does not have a discount (break, subsidy). The word itself may have specified, broader meaning within the insurance industry. The changes imposed in 2012 by Congress appear to be intended to move the NFIP itself toward being more actuarially sound.
Base Flood Elevation (BFE) - The base flood is the 1%-annual-chance flood, commonly called the "hundred year flood." Base Flood Elevation is the water-surface elevation of the base flood. The depth of the base flood can be calculated by subtracting the ground elevation from the BFE. The probability is 1% that rising water will reach BFE height in any year; which compounds over a thirty-year period to 26% or more.
In the flood zone - This term is used by most people to mean the property is in the Special Flood Hazard Area (SFHA), as depicted on the Flood Insurance Rate Map (FIRM). The NFIP flood zones are A and V zones and sometimes have letters or numbers following the A or V (e.g. AE, AH, AO, VE). The officially adopted FIRM is the basis for all flood insurance rating. The community may be using a more restrictive map with broader flood zones and higher flood standards for regulating floodplain development. The community's regulatory map also may include allowances for increased runoff, subsidence, failure of dams and levees, or sea level rise, which are not reflected on the FIRM.
Too low- From an insurance-rating standpoint, "too low" means the elevation of the building is lower than the BFE. Building elevation in the A-zones is measured at the top of the lowest floor. Elevation in the V-zones is measured at the bottom of the lowest horizontal structural member of the foundation. Enclosures that are lower than the living space may be considered the "lowest floor" in some circumstances; machinery and equipment located below the living space may raise insurance rates. The following resources may be helpful:
NFIP Elevation Certificate with lowest floor diagrams
FEMA Technical Bulletin 1-08: Openings in Foundation Walls and Walls of Enclosures
From a practical standpoint, "too low" means the risk of flooding is higher, a fact that has been concealed till now by artificially low (subsidized) insurance rating. The lower you are relative to BFE, the higher your risk of flooding. Being “too low” in the flood zone can cause hardship for the owner if the building is substantially damaged by fire, flood, tornado, earthquake or other event and must be raised before it can be repaired. The cost of raising the building usually is not covered by home owners insurance, but may be offset to some extent by the Increased Cost of Compliance coverage of the NFIP policy.
NFIP Community Status Book - Use this to find out which communities in your state participate in the NFIP, when they entered, and the dates of their first and current Effective FIRM. Data are presented in Adobe PDF, comma separated values (CSV) text file, and HTML formats.
State NFIP Coordinators - maintained by the Association of State Floodplain Managers. State coordinators will know their local floodplain administrators.
Bulletin to NFIP Insurers Regarding Implementation of the Reform Act and other Policy Matters - March 29, 2013.