Cambridge, MA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Set by
- City Engineer
- Projection horizon
- ~50 years from promulgation
- Elevation datum
- Cambridge City Base (CCB)
- Applicable standards
- 1%-LTFE and 10%-LTFE
- Public comment period
- 90 days before final promulgation
- Applies to
- Green Building Projects (Sec. 22.20) and other development
Summary
Cambridge builds to its own forward-looking flood standard instead of just FEMA's historical base flood elevation. The City Engineer sets parcel-by-parcel Long-Term Flood Elevations under Zoning Ordinance Section 22.83, projecting climate-driven flood risk roughly 50 years out.
The City Engineer shall promulgate, and shall revise from time to time, the projected elevations of future flood risk due to certain types and probabilities of flood events for every lot in the City of Cambridge. The resulting projected elevations are referred to herein as Long-Term Flood Elevations ("LTFEs")... LTFEs shall be based on an approximately 50-year projection from the time of promulgation. For example, LTFEs promulgated in or around the year 2020 shall anticipate flood risks in or around the year 2070. The City Engineer shall identify the projected timeframe when promulgating LTFEs. LTFEs shall be represented in vertical feet relative to the Cambridge City Base (CCB) datum.
Full Breakdown
1(a) directs the City Engineer to promulgate, and periodically revise, projected flood elevations for every lot in Cambridge, called Long-Term Flood Elevations (LTFEs). 1(b), precipitation-driven LTFEs come from the city's own hydraulic model, while sea level rise and storm surge LTFEs are based on climate modeling performed or endorsed by Commonwealth of Massachusetts agencies. 1(c) sets the projection window at roughly 50 years, so elevations set around 2020 anticipate flood conditions around 2070, and each promulgation must state its projected timeframe. 1(e)); a licensed surveyor's property survey is treated as more accurate than the city's LIDAR-based ground elevation data, though it cannot change the LTFE itself.
1(f)). 2(b) grandfathers a development that already has a DPW-approved LTFE plan against later, stricter LTFEs, so long as it proceeds continuously to completion. 20 and to other development identified elsewhere in the Zoning Ordinance.
Violations & Fines
Flood elevation compliance is enforced through the Zoning Ordinance's general permitting controls: Section 9.12 bars the Superintendent of Buildings from issuing a building permit or certificate of occupancy for construction that violates the Ordinance, and Section 9.16 authorizes fines up to $300 per offense or per day the violation continues, enforced by the Commissioner of Inspectional Services.
Frequently Asked Questions
What are Cambridge's Long-Term Flood Elevations?
How far into the future do LTFEs project?
Can my own property survey override the city's flood data?
Which projects must meet Cambridge's flood elevation standards?
Sources & Official References
Other rules in Cambridge
Compare Cambridge to another location·View the Massachusetts environmental rules overview
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Flood Elevation Requirements in Nearby Cities
How other cities in this county handle flood elevation requirements.