The agency says the decline followed an 11.3 per cent decrease the previous month.
It says lower construction intentions in the non-residential sector in six provinces, led by Ontario, more than offset a gain in the residential sector.
The value of permits in the non-residential sector fell 8.8 per cent to $2.3 billion in March, the lowest level since January 2013.
In the residential sector, the value of permits rose 1.0 per cent to $3.7 billion, following a 20.8 per cent decrease in February.
The total value of permits was down in five provinces in March, with Ontario posting the largest decline, followed by Quebec and New Brunswick.