Flood maps: how to check if your house is in a flood zone, and what the map does not show

City of Calgary, Flood maps · 2025

The City says these areas have different development rules. New buildings cannot be built in the floodway except a same-footprint replacement of a house, backyard suite or accessory building; in the flood fringe and overland flow areas new buildings and significant additions may be built if designed to prevent structural damage by floodwaters. The City recommends starting with the Government of Alberta Flood Hazard Map, and says recommended flood elevation levels are recommendations only; call 311 for flood elevation information.

City of Calgary, Understand Flooding — Flood maps and river flows · 2026

Alberta released updated Flood Hazard Area maps in May 2025 dividing the hazard area into four categories. Council referred the Calgary report back to Administration on April 28, 2026, to return to Committee in Q4 2026; until then, development applications are assessed under the current Land Use Bylaw. So a Calgary address can sit in two maps at once: the provincial update, and the regulatory map the City still applies.

City of Calgary, Land Use Bylaw 1P2007, Part 3, s. 60 (Building Design in the Flood Fringe) · 2026

Section 61 applies the same requirement in the overland flow area, and additions that increase gross floor area by more than 10 per cent but less than 75 per cent must install one too. The City's new-house guidance says all new houses require a backflow valve if located in the floodway, flood fringe or overland flow areas. This site found no Calgary rule requiring a valve in every home regardless of location.

City of Calgary, Floodway, flood fringe and overland flow · 2026

The City adds that Calgary's updated Flood Hazard Area map is available at floods.alberta.ca, and that the Province's new mapping reflects investments in flood mitigation such as the Springbank Off-Stream Reservoir, which results in lower flood risk for many areas in Calgary.

City of Calgary, Floodway, flood fringe and overland flow · 2026

About the City's Regulatory Flood Map (floodway, flood fringe and overland flow on the Bow, Elbow, Nose Creek and West Nose Creek). Once you know your area, the City says to check the Land Use Bylaw, Part 3 Division 3, for the rules that apply. The City's “flood maps and river flows” page also invites residents to search for their property on its flood and river flow maps, which include inundation maps for different-sized floods.

City of Calgary, Floodway, flood fringe and overland flow · 2026

The City can give both the official flood elevation — set by the Province before the 2013 flood and still the legal minimum for a new building's main floor — and a recommended flood elevation it set after 2013, typically higher and not legally binding. It provides them with a permit application or on request.

City of Calgary, Flood maps and river flows · 2026

Based on a City groundwater study that mapped groundwater levels in a 1-in-100-year flood. Like the rest of the proposed update, it is not adopted: Council referred the report back on April 28, 2026, with a return to Committee planned for Q4 2026 and more engagement in fall 2026.

Government of Alberta, Flood Hazard Identification Program · 2026

The flood hazard area is the land flooded in that design flood, typically divided into the floodway — the highest hazard, where flows are deepest, fastest and most destructive — and the flood fringe, where water is shallower and slower. Alberta calls overland flow a legacy flood fringe sub-zone being phased out, points to its online Flood Awareness Map Application, and warns that flood maps are not available in all communities and flood risks exist in areas without mapping.

Toronto and Region Conservation Authority, Frequently Asked Questions · 2026

For most of TRCA's jurisdiction, TRCA says, it is the Regional Storm: the rainfall and soil conditions of Hurricane Hazel in 1954, which dropped 285 millimetres of rain in 48 hours, transposed over a watershed. Residents can search by address to see whether a property is in a TRCA flood plain, and a property can be in a regulated area without being in the flood plain.

Government of Ontario, Independent Review of the 2019 Flood Events · 2019

Ontario's flood standard for rivers and streams, as the independent review described it. Most flood maps in Ontario are created by municipalities and conservation authorities, the province says; it has committed up to $15 million over four years for flood mapping projects.

Toronto and Region Conservation Authority, TRCA Flood Plain Map · 2026

TRCA's FAQ adds that urban or basement flooding can occur anywhere when there is no overland flow route or the drainage system's capacity is exceeded. A property outside every mapped flood plain can still take water in the basement — which is why the sewer backup endorsement exists.

Natural Resources Canada, Flood Hazard Identification and Mapping Program · 2026

Modified April 27, 2026, under the National Adaptation Strategy; the original investment was $63.8 million from 2021 to 2024. The programme aims to complete flood hazard maps of higher-risk areas with the provinces and territories. NRCan describes floods as the most frequent and costly disaster in Canada, causing over $2 billion in damages annually.

Public Safety Canada, Task Force on Flood Insurance and Relocation · 2026

The commitment is to a low-cost national flood insurance program for homeowners at high risk and without adequate insurance. Public Safety's parliamentary notes record $31.7 million over three years in Budget 2023 and a Budget 2024 commitment to a CMHC subsidiary for flood reinsurance. This site found no official source confirming the program has launched as of September 30, 2026.

Public Safety Canada, Adapting to Rising Flood Risk (2022) · 2022

The same report says the current market fails to cover Canadians in high-risk areas. The flood map and the overland premium are two readings of the same risk.