And at 4:20 p.m. thousands of people will flock to Golden Gate Park to light up and celebrate under a cloud of smoke.
This year the city says the 4/20 holiday will be much more controlled and less chaotic.
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Last year 10,000 people along with all their trash littered the park. San Francisco lawmakers say it cost more than $100,000 for clean-up and security.
City still not sanctioning 4-20 Pot smoking gala at GG Park but will control it to make it safer for thousands expected tomorrow. pic.twitter.com/xYhmwBSxU4— Vic Lee (@vicleeabc7) April 19, 2017
But San Francisco Supervisor President London Breed says it's a tradition in the city that is not likely to change anytime soon.
"This event is going to happen whether we want it to happen or not," said Breed.
The city still won't sanction 4/20 Thursday but it will try to control it.
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"There will be no drug sales, no unauthorized music and no permitted concessions and no alcohol," said Breed.
For the first time, the city will partner with merchants, mostly from the Haight. The group is headed by Alex Aquino, who owns a nearby store.
For the first time, City awards permit to private group headed by Haight merchant Alex Aquino to provide services at 4-20 smoke out. pic.twitter.com/tZtqdldETc— Vic Lee (@vicleeabc7) April 19, 2017
"We want to keep the beautiful park beautiful right? And of course the upper Haight clean and safe," said Aquino.
They've raised $100,000 to help defray the city's costs.
Also new this year, there will be more porta-potties, garbage cans, security, approved food stalls and help with the clean-up afterwards.
And they're paying for a fence around the perimeter with only two entrances to Hippie Hill, manned by security.
"4/20 is no event for children. We do not want children at this event," said Park Police Captain John Sanford.
City Hall says No alcohol, drugs,unauthorized music and no children at 4-20 on Hippie Hill tomorrow. Strict enforcement promised. pic.twitter.com/TPk4w4Akaz— Vic Lee (@vicleeabc7) April 19, 2017
"I think that's ok. It has been really packed and out of control the last few years," said Robert Griffin, a 4/20 participant.
"We've been begging for more porta-potties and garbage cans and all that," said Hank Cancel, a 4/20 participant.
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