Well if the pipes froze , then you also have some water damage .

A lot of other properties in my area were built 1990-2010 and the building construction is much better in terms of materials(copper/pvc pipe vs steel, ect) and I would use 5%.

I am aware that the neighbor had the water shut off from the street because a pipe had burst in the basement one winter.

So much stress... then there was one time, we hired the cheapest guy (don't EVER hire the cheapest guy), which actually ended up costing us $$$ because they stole our copper pipes and we had to redo all the plumbing!   

I am aware that the neighbor had the water shut off from the street because a pipe had burst in the basement one winter.

Same applies for a clogged pipes, new paint, etc.

Is the $3600 I just spent to fix a broken sewer pipe a repair to expense all this year or a capital outlay to be depreciated? 

Copper pipe had been stripped in the basement as well as electrical. 

I assume some portion of the plumbing / piping needs repaired so I'll say $6k to be safe.

Depending on how long it's been neglected those pipes which are in the wall could have rot.