Subleasing your business office for income.

[Manuel Lam]

I have a consulting business (professional corp).  I pay $600 to lease my office (cheap i know). It turns out that it is common practice to sublease other days to offset my lease.  I sublease at $250/day.  So i can get positive cash flow on leasing if I sublease at three days.  

I have active income where I see clients.  I have a rent expense.  I have income from subleasing (passive income).  Is the subleasing passive income separate from my active consulting business?  i.e.  It's a different business in itself, and I would file it as a schedule E? as a sole proprietor?  Should I deposit the passive income into a different account or is that considered commingling?  Seems like a hassle to organize it separately but I see the tax advantages.  Kinda want to just clump it together.  It can offset some business expenses, and it doesn't look like I need to work as hard. 

What are your thoughts?