Flames broke out Thursday morning at an under-construction house in northwest Waterloo.
The fire was discovered around 6:45 a.m. on Ladyslipper Drive, near Columbia Street and Wilmot Line.
Construction workers were able to put it out by using water from a nearby pond.
Officials say the fire is being treated as suspicious, and may be linked to a series of suspicious fires in the area.
Since the beginning of July, there have been nine suspicious fires in Waterloo’s north end.
Damage from Thursday’s fire is estimated at $5,000.