plumbing quote question

[Rene Bee]

Hi Everyone, 

I am starting a 2 family gut rehab and I am getting quotes from plumbers.  I sent the architect drawings to a plumber and he gave me an quote based on the plans.  The quote wasnt very detailed.  

He said the quote included labor, permits, rough materials for plumbing (from service to fixtures/ no fixtures or hardware), all materials and equipment for the hydronic gas boilers, water heaters, gas lines (from service to fixtures), water lines (from service to fixtures) for each floor.
He gave me a quote total: $45,000

This quote seems high to me.  Any thoughts?  The house has 3 bathrooms, 2 kitchens.

Thanks