Last year, Firehouse Subs collected 540 cases of water in its H20 for Heroes campaign from customers at its eight Phoenix area locations.

When they host the campaign today — give a case of 24 bottles of water and get a free medium sub — it hopes to significantly increase that number since its number of Arizona restaurants now sits at a dozen.

The Tucson area's lone Firehouse Subs is at 3844 W. River Road at Thornydale Road in the Marana Marketplace. 

 The offer is good all day today. Firehouse Subs is open from 10 a.m. to 10 p.m. Click here for details or call 219-2322.