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Washingtonian Magazine - Top Agent, 2018, 2019, 2021

GCAAR - Gold Award Winner - Multiple Times

Member of Top Agent Network

National Association of Realtors Green designation


Washingtonian over 20 years and a real estate agent over 15 years

Specialty Historic Properties


American Humane Society

Virginia Thoroughbred Project - Board Member

Supporter of John Eaton Elementary School

Food and Friends

Client Testimonials

"John is the consummate professional and an absolute joy to work with. I had never a property before, and John went above and beyond to advise me throughout the entire process. I was impressed with his ability to accurately predict unforeseen costs, timelines, and multiple other hidden issues. He did so much work before the property was listed that the entire process flowed very smoothly. In fact, I had multiple offers far above the asking price within 3 days of . John will be the first person I contact for my future real estate needs." - Caroline

"We are writing this letter to convey our great satisfaction with our Realtor, John Mammano, who we hired to sell our home. John was particularly helpful to us in many ways. John provided us with an effortless and efficient real estate transaction, from our first meeting to the closing. He explained the process in great detail and because of his professional demeanor and knowledge of the real estate we were confident in his skills and support. He often went the extra mile, specifically in coordinating the transaction while we were out of town and providing us with feedback including all items required for completion on the sellers checklist. John was readily available and able to answer any questions we had. Honestly, we do not know how we would have accomplished this without his help. We have no qualms about recommending John as a realtor who goes above and beyond to please his clients." - Ian & Fran

"John is an amazing real estate agent. He assisted our family in securing a wonderful condo our son. addition to being highly professional, he is very affable and was able to work with inter-generational needs (two parents and one young adult). He was always available to show us places and chat with us about the pros and cons of each apt. Under the last stretch of a bidding up process, which can be stressful, John used his mild manner and professional strategies to accomplish a winning my son. He is the best, do not hesitate to use him. We look forward to working with him again in the future." - Lance, Marjorie & Mark

About John

John has been a Washington resident for over 20 years and a real estate agent for over 15 years. He has built his business on referrals and returning clients who trust his expertise, attention to detail and outstanding negotiation skills. John is known for his sincere business approach, team work with his clients and open communication throughout the real estate transaction. 

John credits his parents for his dedication to hard work and entrepreneurial spirit. Thanks to his family’s construction and real estate investment businesses, John was raised with the notion that hard work, smart business decisions and loving your career are the ingredients for success.

John holds a Bachelor of Arts degree in Political Science and a minor in Business Administration from Arizona State University. His prior years of working in corporate Finance and Project Management prepared him to seamlessly handle complex transactions in real estate.

John’s interests include renovation projects, design and architecture. He takes inspiration from his travels through Argentina, Brazil, Costa Rica, England, France, Spain, Mexico, Italy, Czech Republic and Hungary. As an animal lover, John is a supporter of The Humane Society.

John Mammano’s Listings

a city view with tall buildings and a yard
a living room with furniture and large windows
a living room with furniture potted plant and a large window
a view of a garden
a living room with furniture and a dresser
a view of a hardwood floor and wardrobe
a living room with furniture and a wooden floor
a living room with furniture piano and a bookshelf
a living room with furniture and wooden floor
a bedroom with furniture and white walls
a kitchen with stainless steel appliances granite countertop a sink a stove and cabinets
a kitchen with stainless steel appliances granite countertop a refrigerator sink and white cabinets
a dining room with furniture wooden floor and a rug
a living room with furniture and a large window
a living room with furniture and a potted plant
a view of a hallway with wooden floor and staircase
a bedroom with a bed and chair
a bedroom with a bed and a chair
a bathroom with a sink mirror and toilet
a view of a dining room with furniture
a view of a livingroom with hardwood floor and a large window
a view of a room with gym equipment
a view of a table and chairs in the garden
a view of park with bench and garden
a view of field with trees in the background
a view of a sky
a front view of a building with street
a front view of a building with street view
a car parked in front of a building
a view of a house with a porch
a building outdoor space with patio furniture and a couch
a black and white wall with a potted plant
a sign on the side of the tree
Listed By CompassActive Under Contract


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