Tenant Left Hose Connected During Winter - Who is Responsible?

[Dan Hartzke]

Tenant left the hose connected to the spigot over the winter (live in Midwest where freezing temps occur during Winter).  As a result, the pipe was not able to drain properly and once below freezing temperatures came, the pipe burst in the basement.   The tenant did not become aware of the pipe burst until Mid-June and was using the hose for spring and summer.  Resulting in a decent amount of water damage in the basement.  I submitted a claim to get the water damage restoration process started and replace the burst pipe.  Total damages included water restoration cost, pipe replacement and drywall/insulation repair/replacement.  

Who is at fault for the damages?  Landlord or Tenant?