Hamilton Radon Map: Every Home Health Canada Tested, and What It Read

207 homes across Hamilton were long-term tested for radon in the two federal surveys. Every one is a dot on this map, coloured by what it read, with the number of tested homes printed beside every district figure.

The Map

Every dot is one tested house. Zoom in for street names. Shaded districts had no home tested in either survey. This page covers postal districts L8 and L9. The whole province is on the Ontario map.

under 100100 to 147148 to 199200 and aboveno homes tested

207 measurements shown. Dot positions inside a district are illustrative, not addresses. The survey records which district a home was in, never where it stood. Tap any dot for its reading, or any district for its count and median. Rural districts here cover thousands of square kilometres, so a dot in one says very little about any particular corner of it.

Built from Health Canada's published measurements under the Open Government Licence. We do not sell radon testing or mitigation.

What the Numbers Say

6%
of tested Hamilton homes at or above Canada's 200 Bq/m³ action level
56
median reading, Bq/m³
569
highest single reading, in L9W

Hamilton sits 30th of the 33 places mapped with a hundred or more tested homes, at 6.3% at or above the action level, between Halifax at 35.2% and Toronto and the GTA at 2.2%. All on the same two surveys and the same method. The spread between places is real, and the spread between houses on one street is bigger still.

The Number Changes Depending on Whose Limit You Use

Canada acts at 200 Bq/m³. The United States EPA acts at about 148. The World Health Organization sets a reference level of 100. Applied to the same 207 homes:

6%
at or above Canada's 200
11%
at or above the US EPA's 148
25%
at or above the WHO's 100

Same houses, same measurements. Why the three numbers differ, and which one to use.

By Postal District, with the Sample Sizes Shown

Read the count column before the median column. A district resting on four houses is a hint, not a verdict, and those rows are greyed. The land area column matters too: a district covering ten thousand square kilometres is an average across a region, not a neighbourhood.
DistrictLand km²Homes testedMedianHighestAt or over 200
L9G81121345153
L9M24321311850
L8S1841161690
L8T691162152
L9S11931111300
L9C139833982
L8W76762481
L9H6214742161
L9L237271960
L8G94631600
L8R44631180
L9W68322605694
L8M3259730
L9B14759870
L8P69551100
L8V610531280
L8E33752900
L8J7112521570
L8N76521950
L9R1034481440
L8K1210441340
L9A7943960
L9K8739990
L8L13636530
L9N69533880
L9T83932760
L8H167291580
L9Y186129290
L9Z57327370
L9P218223290

6 districts have ten or more tested homes, which is where these figures start to mean something. The districts with no measurement at all are L8B, L9E, L9J, L9V, L9X.

What Actually Settles It

Nothing on this page describes your house. Radon varies enormously between homes on the same street, because it depends on how each building sits on and draws air from the ground beneath it. The highest reading here is 569 Bq/m³ and it sits in a district whose median is far below it. A long-term test in your own home is the only measurement that tells you anything about your home.

Also: every C-NRPP certified radon company here, the other city and province maps, and what radon actually is.

Sources and method. Radon measurements: Health Canada, Radon and Thoron Data From Canadian Homes pooled with the Cross-Canada Survey of Radon Concentrations in Homes 2009-2011, both under the Open Government Licence – Canada. Boundaries: Statistics Canada 2021 cartographic forward sortation area file, same licence. Percentages are calculated from the individual measurements shown, not quoted from a summary. Land areas are from the Statistics Canada boundary file.