Landlord or tenant responsibility for repair?

[Brad S.]

My tenant reported a bursting pipe when trying to use an outdoor faucet the first time in spring.  The home was a new construction and still within the builder's warranty, but the builder denied warranty saying it was misuse (garden hose should not be attached to outdoor faucet in winter).  Tenant first argued his neighbor's hose was connected all winter but they don't have any problem, then tenant claimed the hose was disconnected.  I had several plumbers looked at the cracked sillcock, all agreed the cause of the burst pipe should be the attached hose in winter.  The install of the outdoor faucet was correct with sufficient pitch to go downwards.  That's why builder denied warranty because it was not wrong installation or product defect.

I told the tenant he should be responsible because the lease addendum said:"landlord is responsible for major structure repairs and defect product repairs, tenant is responsible for any maintenance repair or repair caused by tenant misuse or neglect."

Before thanksgiving, I sent one courtesy reminder to tenant to ask them to remove garden hose for winter. Tenant now argued back said he could have neighbor wrote a statement as witness that he did remove the hose in winter after thanksging.  So the sillcock must be broken before thanksgiving that was before I sent the email reminder.  Tenant showed low temp of Nov.  The were 3 low temperature days of about 20-26F.  I looked at those 3 days even low went to 20F, high temp for those 3 days were all in the 40F - 55F.    Tenant said I failed to remind him that's how the hose was connected before thanksgiving, that caused the burst pipe.  He was from Texas, he connected the hose all the time in Texas, he should not know the hose should be disconnected for winter in our area if I did not tell him.  He said he did disconnect after I reminded him after thanksgiving.

Should I be responsible for Tenant's misuse?  He was originally from Missouri, then moved to Texas, then to our area, I assumed he should have the knowledge of knowing attached hose in winter can cause pipe burst.  Besides it was a frost free outdoor faucet.  On the faucet plate it clearly marked "remove hose or pipe may burst".  Is that enough to remind tenant even if I did not remind early enough?  He can claim he does not know because he is from Texas, or he can claim the warning on the outdoor faucet is too small to notice.  But if these excuses can pass, everything can be landlord's fault if tenant misuse or neglect to do something, they can just say they do not know and landlord did not remind them.

I blamed myself for not going there after thanksgiving to check to see if the hose was actually removed.  I believed it was the Dec and Jan temp we had that caused the issue (when high temp was 1-10F, low -1F). 

From this incident, I would like to know how you decide whose responsibility it is for repair.  Seems like all mystery damages can cause arguments.

I would appreciate any advice or suggestions.  Thanks in advance !