High risk to property & infrastructure, low risk to public safety
The greatest threat beavers pose to human property and infrastructure is through flooding and water damage. Beavers are highly efficient and obligate dam builders compelled by instant to plug any flowing water features. They do not limit dam construction to streams and creeks; culverts, storm drains, pond inlets and outlets, and sometimes even sizable rivers can be partially obstructed if not fully dammed. Dams and blockages once in place can flood large areas in relatively short periods of time, especially following rainfall.
The flow-obstruction instinct of beavers also wreaks havoc with industrial water intakes and drains, sometimes in hard-to-reach areas, causing silt accumulation, machinery damage, and work stoppages until they can be removed and flow restored.
As tree herbivores, beavers can also damage and destroy significant trees in parks and subdevelopments with wetland and pond features, damage which can accumulate to tens of thousands of dollars for the costs and values provided by planted trees. A tree in the process of being cut down by a beaver is also a significant public safety hazard on windy days.
Beavers in general do not attack humans and avoid contact unless habituated. They are capable of carrying rabies, but actual rates of occurrence are very rare.