Pot is trying to go legit, and in many states in the U.S. it is now technically legal. Despite this, the black market for marijuana continues to thrive, with illegal sales still very common.

Growers blame government oversight and taxation. Going legal means getting permits at the county and state level (and often city); the application process can cost tens of thousands of dollars or even more. Inspections and compliance with laws costs more money as well. And then there are the taxes.

California, for example, currently taxes marijuana at 15%. That’s in addition to the normal state sales tax and any county or city taxes that may be applied as well. Experts say all of this combined makes legal marijuana around 45% more expensive than black market marijuana. For many people that’s enough savings to stay illegal.

California is trying to change that now, and many other states are wising up to the issue as well. California is moving to reduce the state tax to 11%. Though that is a step in the direction of greater legalization, it’s still not enough to entirely fix the problem.

A recent Netflix documentary “Murder Mountain” details the struggles of small growers going to go legal in Humboldt County, on the Northern California coast, known internationally as a marijuana-growing center. Growers are going into massive debt in hopes of being able to make it all back when they are legal. It remains to be seen if those growers will be able to dig themselves out of that hole.

In the meantime, local and state governments will have to deal with the problem of semi-legal marijuana.