---
kind: "section"
citation: "42 U.S.C. § 4101b"
title: "42"
title_heading: "The Public Health and Welfare"
number: "4101b"
heading: "National Flood Mapping Program"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/42/4101b"
units:
  - "Chapter 50 — National Flood Insurance"
  - "Subchapter III — Coordination of Flood Insurance with Land-Management Programs in Flood-Prone Areas"
---

# §4101b. National Flood Mapping Program

- (a) **Reviewing, updating, and maintaining maps—** The [Administrator](/usc/42/4003.md?p=a-6), in coordination with the Technical Mapping Advisory Council established under [section 4101a of this title](/usc/42/4101a.md), shall establish an ongoing program under which the [Administrator](/usc/42/4003.md?p=a-6) shall review, update, and maintain [National Flood Insurance Program](/usc/42/4004.md?p=a-4) rate maps in accordance with this section.
- (b) **Mapping—**
  - (1) **In general—** In carrying out the program established under [subsection (a)](#a), the [Administrator](/usc/42/4003.md?p=a-6) shall—
    - (A) identify, review, update, maintain, and publish [National Flood Insurance Program](/usc/42/4004.md?p=a-4) rate maps with respect to—
      - (i) all populated areas and areas of possible population growth located within the [100-year floodplain](/usc/42/4004.md?p=a-1);
      - (ii) all populated areas and areas of possible population growth located within the [500-year floodplain](/usc/42/4004.md?p=a-2);
      - (iii) areas of residual risk, including areas that are protected by levees, dams, and other [flood](/usc/42/4121.md?p=a-1) control structures;
      - (iv) areas that could be inundated as a result of the failure of a levee, dam, or other [flood](/usc/42/4121.md?p=a-1) control structure;
      - (v) areas that are protected by non-structural [flood](/usc/42/4121.md?p=a-1) mitigation features; and
      - (vi) the level of protection provided by [flood](/usc/42/4121.md?p=a-1) control structures and by non-structural [flood](/usc/42/4121.md?p=a-1) mitigation features;
    - (B) establish or update [flood](/usc/42/4121.md?p=a-1)-risk zone data in all such areas, and make estimates with respect to the rates of probable [flood](/usc/42/4121.md?p=a-1) caused loss for the various [flood](/usc/42/4121.md?p=a-1) risk zones for each such area; and
    - (C) use, in identifying, reviewing, updating, maintaining, or publishing any [National Flood Insurance Program](/usc/42/4004.md?p=a-4) rate map required under this section or under the National [Flood](/usc/42/4121.md?p=a-1) Insurance Act of 1968 ([42 U.S.C. 4011](/usc/42/4011.md) et seq.), the most accurate topography and elevation data available.
  - (2) **Mapping elements—** Each map updated under this section shall—
    - (A) assess the accuracy of current ground elevation data used for hydrologic and hydraulic modeling of flooding sources and mapping of the [flood](/usc/42/4121.md?p=a-1) hazard and wherever necessary acquire new ground elevation data utilizing the most up-to-date geospatial technologies in accordance with guidelines and specifications of the Federal Emergency Management [Agency](/usc/42/8262.md?p=1); and
    - (B) develop [National Flood Insurance Program](/usc/42/4004.md?p=a-4) [flood](/usc/42/4121.md?p=a-1) data on a watershed basis—
      - (i) to provide the most technically effective and efficient studies and hydrologic and hydraulic modeling; and
      - (ii) to eliminate, to the maximum extent possible, discrepancies in base [flood](/usc/42/4121.md?p=a-1) elevations between adjacent political subdivisions.
  - (3) **Other inclusions—** In updating maps under this section, the [Administrator](/usc/42/4003.md?p=a-6) shall include—
    - (A) any relevant information on coastal inundation from—
      - (i) an applicable inundation map of the Corps of Engineers; and
      - (ii) data of the National Oceanic and Atmospheric Administration relating to storm surge modeling;
    - (B) any relevant information of the [United States](/usc/42/4121.md?p=a-2) Geological Survey on stream flows, watershed characteristics, and topography that is useful in the identification of [flood](/usc/42/4121.md?p=a-1) hazard areas, as determined by the [Administrator](/usc/42/4003.md?p=a-6);
    - (C) any relevant information on land subsidence, coastal erosion areas, changing lake levels, and other [flood](/usc/42/4121.md?p=a-1)-related hazards;
    - (D) any relevant information or data of the National Oceanic and Atmospheric Administration and the [United States](/usc/42/4121.md?p=a-2) Geological Survey relating to the best available science regarding future changes in sea levels, precipitation, and intensity of hurricanes; and
    - (E) any other relevant information as may be recommended by the Technical Mapping [Advisory Committee](/usc/42/17061.md?p=2).
- (c) **Standards—** In updating and maintaining maps under this section, the [Administrator](/usc/42/4003.md?p=a-6) shall—
  - (1) establish standards to—
    - (A) ensure that maps are adequate for—
      - (i) [flood](/usc/42/4121.md?p=a-1) risk determinations; and
      - (ii) use by [State](/usc/42/4121.md?p=a-2) and local governments in managing development to reduce the risk of flooding; and
    - (B) facilitate identification and use of consistent methods of data collection and analysis by the [Administrator](/usc/42/4003.md?p=a-6), in conjunction with [State](/usc/42/4121.md?p=a-2) and local governments, in developing maps for [communities](/usc/42/4003.md?p=a-1) with similar [flood](/usc/42/4121.md?p=a-1) risks, as determined by the [Administrator](/usc/42/4003.md?p=a-6); and
  - (2) publish maps in a format that is—
    - (A) digital geospatial data compliant;
    - (B) compliant with the open publishing and data exchange standards established by the Open Geospatial [Consortium](/usc/42/17061.md?p=4); and
    - (C) aligned with official data defined by the National Geodetic Survey.
- (d) **Communication and outreach—**
  - (1) **In general—** The [Administrator](/usc/42/4003.md?p=a-6) shall—
    - (A) before commencement of any mapping or map updating process, notify each [community](/usc/42/4003.md?p=a-1) affected of the model or models that the [Administrator](/usc/42/4003.md?p=a-6) plans to use in such process and provide an explanation of why such model or models are appropriate;
    - (B) provide each [community](/usc/42/4003.md?p=a-1) affected a 30-day period beginning upon notification under [subparagraph (A)](#d-1-A) to consult with the [Administrator](/usc/42/4003.md?p=a-6) regarding the appropriateness, with respect to such [community](/usc/42/4003.md?p=a-1), of the mapping model or models to be used; provided that consultation by a [community](/usc/42/4003.md?p=a-1) pursuant to this subparagraph shall not waive or otherwise affect any right of the [community](/usc/42/4003.md?p=a-1) to appeal any [flood](/usc/42/4121.md?p=a-1) hazard determinations;
    - (C) upon completion of the first Independent Data Submission, transmit a copy of such Submission to the affected [community](/usc/42/4003.md?p=a-1), provide the affected [community](/usc/42/4003.md?p=a-1) a 30-day period during which the [community](/usc/42/4003.md?p=a-1) may provide data to [Administrator](/usc/42/4003.md?p=a-6)[^1] that can be used to supplement or modify the existing data, and incorporate any data that is consistent with prevailing engineering principles;
    - (D) work with [States](/usc/42/4121.md?p=a-2), local [communities](/usc/42/4003.md?p=a-1), and property [owners](/usc/42/13641.md?p=4) to identify areas and features described in [subsection (b)(1)(A)(v)](#b-1-A-v);
    - (E) work to enhance communication and outreach to [States](/usc/42/4121.md?p=a-2), local [communities](/usc/42/4003.md?p=a-1), and property [owners](/usc/42/13641.md?p=4) about the effects—
      - (i) of any potential changes to [National Flood Insurance Program](/usc/42/4004.md?p=a-4) rate maps that may result from the mapping program required under this section; and
      - (ii) that any such changes may have on [flood](/usc/42/4121.md?p=a-1) insurance purchase requirements;
    - (F) engage with local [communities](/usc/42/4003.md?p=a-1) to enhance communication and outreach to the residents of such [communities](/usc/42/4003.md?p=a-1), including tenants (with regard to contents insurance), on the matters described under [subparagraph (E)](#d-1-E);
    - (G) not less than 30 days before issuance of any preliminary map, notify the Senators for each [State](/usc/42/4121.md?p=a-2) affected and each Member of the House of Representatives for each congressional district affected by the preliminary map in writing of—
      - (i) the estimated schedule for—
        - (I) [community](/usc/42/4003.md?p=a-1) meetings regarding the preliminary map;
        - (II) publication of notices regarding the preliminary map in local newspapers; and
        - (III) the commencement of the appeals process regarding the map; and
      - (ii) the estimated number of homes and businesses that will be affected by changes contained in the preliminary map, including how many structures will be[^2] that were not previously located in an area having special [flood](/usc/42/4121.md?p=a-1) hazards will be located within such an area under the preliminary map; and
    - (H) upon the issuance of any proposed map and any notice of an opportunity to make an appeal relating to the proposed map, notify the Senators for each [State](/usc/42/4121.md?p=a-2) affected and each Member of the House of Representatives for each congressional district affected by the proposed map of any action taken by the [Administrator](/usc/42/4003.md?p=a-6) with respect to the proposed map or an appeal relating to the proposed map.
  - (2) **Required activities—** The communication and outreach activities required under [paragraph (1)](#d-1) shall include—
    - (A) notifying property [owners](/usc/42/13641.md?p=4) when their properties become included in, or when they are excluded from, an area covered by the mandatory [flood](/usc/42/4121.md?p=a-1) insurance purchase requirement under [section 4012a of this title](/usc/42/4012a.md);
    - (B) educating property [owners](/usc/42/13641.md?p=4) regarding the [flood](/usc/42/4121.md?p=a-1) risk and reduction of this risk in their [community](/usc/42/4003.md?p=a-1), including the continued [flood](/usc/42/4121.md?p=a-1) risks to areas that are no longer subject to the [flood](/usc/42/4121.md?p=a-1) insurance mandatory purchase requirement;
    - (C) educating property [owners](/usc/42/13641.md?p=4) regarding the benefits and costs of maintaining or acquiring [flood](/usc/42/4121.md?p=a-1) insurance, including, where applicable, lower-cost preferred risk policies under the National [Flood](/usc/42/4121.md?p=a-1) Insurance Act of 1968 ([42 U.S.C. 4011](/usc/42/4011.md) et seq.) for such properties and the contents of such properties;
    - (D) educating property [owners](/usc/42/13641.md?p=4) about [flood](/usc/42/4121.md?p=a-1) map revisions and the process available to such [owners](/usc/42/13641.md?p=4) to appeal proposed changes in [flood](/usc/42/4121.md?p=a-1) elevations through their [community](/usc/42/4003.md?p=a-1), including by notifying local radio and television stations; and
    - (E) encouraging property [owners](/usc/42/13641.md?p=4) to maintain or acquire [flood](/usc/42/4121.md?p=a-1) insurance coverage.
- (e) **Community remapping request—** Upon the adoption by the [Administrator](/usc/42/4003.md?p=a-6) of any recommendation by the Technical Mapping Advisory Council for reviewing, updating, or maintaining [National Flood Insurance Program](/usc/42/4004.md?p=a-4) rate maps in accordance with this section, a [community](/usc/42/4003.md?p=a-1) that believes that its [flood](/usc/42/4121.md?p=a-1) insurance rates in effect prior to adoption would be affected by the adoption of such recommendation may submit a request for an update of its rate maps, which may be considered at the [Administrator](/usc/42/4003.md?p=a-6)’s sole discretion. The [Administrator](/usc/42/4003.md?p=a-6) shall establish a protocol for the evaluation of such [community](/usc/42/4003.md?p=a-1) map update requests.
- (f) **Authorization of appropriations—** There is authorized to be appropriated to the [Administrator](/usc/42/4003.md?p=a-6) to carry out this section $400,000,000 for each of fiscal years 2013 through 2017.

## Footnotes

[^1]: So in original. Probably should be preceded by “the”.
[^2]: So in original. The words “will be” probably should not appear.

## Source credit

(Pub. L. 112–141, div. F, title II, § 100216, July 6, 2012, 126 Stat. 927; Pub. L. 113–89, §§ 27, 30, Mar. 21, 2014, 128 Stat. 1033, 1034.)

## Notes

### Editorial Notes

### References in Text

The National Flood Insurance Act of 1968, referred to in subsecs. (b)(1)(C) and (d)(2)(C), is title XIII of Pub. L. 90–448, Aug. 1, 1968, 82 Stat. 572, which is classified principally to this chapter. For complete classification of this Act to the Code, see Short Title note set out under section 4001 of this title and Tables.

### Codification

Section was enacted as part of the Biggert-Waters Flood Insurance Reform Act of 2012, and also as part of the Moving Ahead for Progress in the 21st Century Act, also known as the MAP–21, and not as part of the National Flood Insurance Act of 1968 which comprises this chapter.

### Amendments

2014—Subsec. (b)(1)(A)(v), (vi). Pub. L. 113–89, § 27(1), added cl. (v), redesignated former cl. (v) as (vi), and, in cl. (vi), inserted “and by non-structural flood mitigation features” before semicolon at end.

Subsec. (d)(1)(A). Pub. L. 113–89, § 30(3), added subpar. (A). Former subpar. (A) redesignated (D).

Pub. L. 113–89, § 27(2)(C), added subpar. (A). Former subpar. (A) redesignated (B).

Subsec. (d)(1)(B). Pub. L. 113–89, § 30(3), added subpar. (B). Former subpar. (B) redesignated (E).

Pub. L. 113–89, § 27(2)(A), redesignated subpar. (A) as (B). Former subpar. (B) redesignated (C).

Subsec. (d)(1)(C). Pub. L. 113–89, § 30(3), added subpar. (C). Former subpar. (C) redesignated (F).

Pub. L. 113–89, § 30(1), substituted “subparagraph (E)” for “subparagraph (B)” and struck out “and” at end.

Pub. L. 113–89, § 27(2)(A), (B), redesignated subpar. (B) as (C) and substituted “subparagraph (B)” for “subparagraph (A)”. Former subpar. (C) redesignated (D).

Subsec. (d)(1)(D). Pub. L. 113–89, § 30(2), redesignated subpar. (A) as (D). Former subpar. (D) redesignated (H).

Pub. L. 113–89, § 27(2)(A), redesignated subpar. (C) as (D).

Subsec. (d)(1)(E), (F). Pub. L. 113–89, § 30(2), redesignated subpars. (B) and (C) as (E) and (F), respectively.

Subsec. (d)(1)(G). Pub. L. 113–89, § 30(4), added subpar. (G).

Subsec. (d)(1)(H). Pub. L. 113–89, § 30(2), redesignated subpar. (D) as (H).

### Statutory Notes and Related Subsidiaries

### Definitions

For definitions of terms used in this section, see section 4004 of this title.