Umbrella liability insurance covering personal+ business assets?

[Mary Jay]

Hi guys,

will you please be so kind and let me know if its a wise thing to do to have an umbrella liability policy covering my personal assets (car, my house) plus my real estate investments (rentals) ?

If I have an umbrella liability policy covering both, then if a tenant sues does it open an access to my personal assets ? 

What about other assets (other rentals)?