What are the legal and property insurance implications for Mom (85) who discovers "medical marijuana" is grown on her property?

Are you saying that your Mom's tenants have a license from the State to grow the medical marijuana? If that is a yes, there shouldn't be an issue. But I would double check with the State to see if that is correct, and how you can check that the tenants actually do have a legit license to grow said product.

Have an attorney look at the lease to see how easy or difficult it would be to get rid of them. She doesn't need this kind of worry at this stage of life. If they aren't under written lease, have the attorney serve them with an eviction notice giving them thirty days to get out. Be prepared to take them to court when they don't leave. I believe any attorney you engage must be licensed to practice law in California.

Keep mom out of it. Mom should hire a property manager to handle this for her. She doesn't need to be in a middle of this kind of problem.

She should say nothing to her insurance company.

California SB420 sets a baseline statewide guideline of 6 mature or 12 immature plants, and 1/2 pound (8 oz.) processed cannabis per patient. Individual cities and counties are allowed to enact higher, but not lower, limits than the state standard. Check the local laws for her property, because it sounds like they have more than 6 plants if there is a sprinkler system. If they are in violation, tell them to comply, in writing.

at their most legal they are still in violation of federal law and one little oversight can result in a raid and possible seizure of property . the tenants have every reason to lie about their compliance to state laws because to remain in compliance is quite costly and takes the profit right out of cultivating . i wouldnt chance it with my property . then theres always the threat of armed robbery of the pot .

Houseplant, just play by the rules. If they are breaking the law and you don't turn them in, your neighbors will and the feds will confiscate the whole property UNLESS you ask for help.

Thank you for the SB420 information. I will research this.

It began month-to-month. An additional 3 months was tacked on. We don't know if she just allowed it to lapse back to a month-to-month as we noticed no definite lease period. But yes, she is also afraid of making waves. There was reference to insurances but not having the full lease in front of me, I'm not sure how it was worded. Mom now says she won't contact her insurance company for the time being as my brother and I have told "everyone else" says don't do it. There were verbal discussions about sprinklers. The lease mentions nothing about work performed. I did notice receipts indicating Mom allowed them to be reimbursed indirectly - i.e. rent for that month was discounted based on actual costs of materials. She thought they were solely helping restore the well house. At the same time they put in the sprinklers. Several months later former neighbors tipped off our mom. Prior to the move-in there were no discussions about pot. I think this is a teachable moment in that all leases statewide should be required to spell out the limits set by SB420.

Houseplant102, have your Mom tell the tenants that the lease will end in 30 days or 60 days or 90 days, how ever the extension was given.

Here's an idea, have Mom say she is putting the house on the market For Sale starting the first of November. No tenant, who is growing what could be an illegal substance, would want people walking through the house nosing around.

Will run this by my brother and mom. We hadn't entertained the idea of telling them the place is going to be for sale.

I'll mention to Mom the need to be pro-active legally speaking. Demonstrating to all entities, should the need arise, that she is attempting to solve this problem. Very good point- if we don't do it, some neighbors may do it. I'm wondering if the neighbors actions of tipping off owner and their being very uneasy would help support the cause.