Matt Sweeney is a registered, licensed and insured Master Plumber in good standing. 
His original Certificate of Competency as a Master Plumber (1999) is from The Incorporated Village of Floral Park#579.
He also holds a Town of Hempstead Tri-Town License  #2889, which means he can work in and secure permits through reciprocation with ANY township or Village within Nassau County and several Suffolk County Townships, if needed

IS THE PLUMBER YOU HIRED
ACTUALLY A LICENSED MASTER PLUMBER?
--> ASK TO SEE THEIR LICENSES.

Master Plumber License Certificate for Matthew Sweeney, Mad Dog LLC -- Floral Park New York
International Code Council - Matt Matt

IS THE PLUMBER YOU HIRED
ACTUALLY A PLUMBER IN GOOD STANDING IN YOUR TOWN?
--> ASK TO SEE THEIR LETTER.

IS THE PLUMBER YOU HIRED ACTUALLY A FLORAL PARK LICENSED MASTER PLUMBER IN GOOD STANDING?
Master Plumber's License for Town of Hempstead - Matt Sweeney, Mad Dog Plumbing, Steam Heat and Radiant Heat