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Lehigh County, PA Environmental Rules: Flood Elevation Requirements (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Flood elevation source
municipal FIRM, § 492.21
Street elevation limit
no more than 1 ft below Reg. Flood Elevation
Sewer/water systems
floodproofed to Regulatory Flood Elevation
Soil absorption sewage systems
prohibited in flood plain, § 492.27
Applies only in
municipalities without own SALDO

Summary

Lehigh County's SALDO ties floodplain design to a Regulatory Flood Elevation drawn from the municipal FEMA flood insurance rate map, or estimated 100-year data where no map exists. Streets can sit no more than one foot below that elevation, and sanitary sewer, water and other utility systems must be floodproofed or elevated up to it.

City-specific rules exist: Allentown has its own flood elevation requirements rules that differ from Lehigh County's county-level regulations. If you live in Allentown, check the city-specific page instead.

492.21 The flood elevation map shall be based on the municipal flood insurance rate map (FIRM). When not available, the map shall be based on estimated 100-year flood elevations or estimated areas subject to flooding based on best available data. ... 492.25 The finished elevation of proposed streets shall not be more than the one (1) foot below the Regulatory Flood Elevation. The LVPC may require profiles and elevations of streets to determine compliance with the requirements. 492.26 All sanitary sewer systems, whether public or private, shall be floodproofed up to the Regulatory Flood Elevation. ... 492.28 All water systems, whether public or private, shall be flood-proofed up to the Regulatory Flood Elevation. 492.29 All other public and private utilities and facilities including gas and electric shall be elevated or flood-proofed up to the Regulatory Flood Elevation.

Full Breakdown

21 requires the flood elevation map used for a project to be based on the municipal Flood Insurance Rate Map (FIRM), falling back to estimated 100-year flood elevations or estimated flood-prone areas from the best available data where no FIRM covers the site. 25 caps how low a proposed street's finished elevation can sit relative to the Regulatory Flood Elevation: no more than one foot below it, with the LVPC empowered to demand street profiles and elevation data to verify compliance, and drainage openings must be sized to pass flood flows without worsening flood heights.

27; water systems must likewise be flood-proofed up to that elevation; and all other public and private utilities, including gas and electric service, must be elevated or flood-proofed to the same benchmark. 1 confines this reach to municipalities that have not adopted their own subdivision ordinance, so the governing elevation standard for most Lehigh Valley parcels comes from the municipality's own floodplain management ordinance and FEMA-derived base flood elevation, not this county text.

Violations & Fines

A violation of these elevation and floodproofing requirements falls under Section 621's general enforcement scheme: a fine of up to $500 per day per violation plus court costs and County legal expenses, with five days to begin correction and thirty days to complete it after written notice from the LVPC or Lehigh County Solicitor, and each day of continued noncompliance treated as a separate offense.

Frequently Asked Questions

What elevation must new streets in a floodplain meet in Lehigh County?
Under Section 492.25 of the county SALDO, a proposed street's finished elevation cannot sit more than one foot below the Regulatory Flood Elevation, and the LVPC can demand street profiles and elevation data to confirm compliance before approving the plan.
Do utilities need to be floodproofed under this rule?
Yes. Sections 492.26 through 492.29 require sanitary sewer systems, water systems, and other public and private utilities including gas and electric to be floodproofed or elevated up to the Regulatory Flood Elevation, and soil absorption sewage disposal systems are barred outright in flood plain areas.
Where does the Regulatory Flood Elevation number come from?
Section 492.21 bases it on the municipality's FEMA Flood Insurance Rate Map; where no FIRM is available for the site, the county uses estimated 100-year flood elevations or estimated flood-prone areas drawn from the best available data.

Sources & Official References

Other rules in Lehigh County

All Lehigh County rules

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Flood Elevation Requirements in Cities Across Lehigh County