Indeed, this year's race is so green that the city hopes to have it certified by a national sports sustainability organization.
Large events - the city expects to see nearly 30,000 runners and at least double that number of spectators - "can generate a tremendous amount of waste," said city sustainability coordinator Katherine Gajewski.
Which isn't quite the desired image for a city whose mayor has said he wants to make it the greenest in America.
So after discussions and pilot projects, organizers have been hoofing it to transform the experience.
Got an empty coffee cup? (If you got it from a marathon vendor, it won't be styrofoam.) Keep a lookout for one of the city's new waste stations - three-part affairs made of recycled plastic milk jugs, with separate bins for recyclables, compostables and actual trash.
Confused about which one your stuff belongs in? Organizers put the word out to college and environmental groups and actually got 200 volunteers to agree to stake out the receptacles and help people sort their waste.
They consider it not just a throwaway moment. In that ten-second interaction with a "waste watcher," someone may forever change the way they dispose of their coffee cups, Gajewski said.
Ultimately, the city aims to divert 75 percent of the waste from the landfill.
And check out the bins themeslves, because you'll likely be seeing them again. SCA, a global hygiene and forest products company with its North American headquarters in Philadelphia, donated 500 of them to the city, at a cost of $175,000. They'll be making repeat appearances at many city events.
Spokeswoman Amy Bellcourt said the company was looking for a way to partner with the city's sustainability efforts, and they came up with this.
"Heat sheets" given to runners at the finish line to keep them warm will be collected and recycled.
Paper is a no-no this year. Handouts have been reduced by 50 percent. Runners were encouraged to register online.
The organizers have been pushing for visitors to use public transportation to get around the city.
Leftover food and warm-up clothing discarded at the starting line will go to area shelters.
Everything will be tallied afterward and submitted to the Council for Responsible Sport, which will determine just how green the event actually was. The city is going for silver, which is behind gold and evergreen.
Modeled after the point system of the U.S. Green Building Council's LEED program for buildings, the "ReSport" program has certified 45 events, mostly marathons and triathlons.
"These events don't exist in a vacuum," said Executive director Keith Peters, a former Nike executive. "They exist in a community, and they impact a community, for better or worse."
His organization's goal is to help them aim for "better," and he says the certification is both a truthing process - so organizers can see exactly how well they've done - and a validation.
"Let's call it credible PR," Peters said.
He said Philadelphia's marathon is "on track to do real well." He loves that the tent companies were asked to come up with a hold-down method other than 55-gallon drums filled with water. "That was a cool one."
The city won't overtake the likes of the gold-ranked Big Sur Marathon, near San Francisco, which boasted a 97 percent waste diversion rate last year. It even has finish line electronics fueled by solar power and BYOB stations - people with water pitchers ready to fill your bottle - on the course.
But the race is on.
Contact Sandy Bauers at 215-854-5147, firstname.lastname@example.org, or follow on Twitter @sbauers. Read her blog, GreenSpace, at www.philly.com/greenspace