We believe we have someone smoking MJ in one of our properties

[Cali Skier]

So we went to the property on a maintenance request, and saw a e-cigerette out on the counter.  We have gone into the house an additional time to check on the AC vents and smelled MJ in the house.  

At that time we said we wanted to do a general inspection of the rooms but the tennant's son was there and said that his mom did not expect an inspectoin and woudl not like us to go into those rooms as they had not had a chance to clean them up.  so we expected that.  

We have a very strick no smoking policy on the property that the tennant has to sign before taking the keys.  We have the lease with the Mom, not the son.  We think its the son doing it.  The mom travels a lot.

What is the right approach here?

[Wesley W.]

Quote from @Greg H.:

You might not be cut out to be a landlord if you think you can micromanage your tenants.  Medical marijuana is legal and vaping does zero damage to a property.  Smoking cigarettes in a unit does damage due to tar and nicotine which is not a factor with marijuana especially vaping 

I think you're coming off a bit dismissive, Greg.  To be honest, I was surprised by your response.

Medical marijuana may be legal, but it should be ingested in ways that are consistent with the signed contract.  If the tenants agreed not to smoke inside, that means not smoking inside.  It's not a judgement; it's the executed agreement that both parties signed.  This is even more important in multi-family buildings, as the smoke permeates through the entire building envelope and common areas, and itcan be a nuisance - especially if someone moved into a building that forbade smoking in the lease.

Marijuana smoke does indeed do damage to the walls.  I just had a turnover where the top third of all the walls had to be scrubbed down due to the pot residue.  (Pic below shows the soot encapsulated in the water droplets after a pass with a sponge.  It took 3 hours to clean thew walls of the 425 sq ft space.) 

To the OP:  you can buy test strips on Amazon on test for pot residue on the walls, but my preferred take is this lease provision:

SMOKING: Smoking is prohibited inside your unit or in any interior common areas. This includes marijuana as well as electronic cigarettes (i.e. “vaping”). You agree to pay an additional $200.00 lease violation fee each time we determine, at our sole discretion, that smoking has occurred in your Rental Unit, due as Additional Rent. Payment of this fee by you does not represent a waiver by us for this breach of the Lease. Smoking leaves soot and deposits, so an additional cleaning/remediation fee of at least $250.00 per room/area will be charged if we determine that smoking/vaping has occurred. Any cigarette butts from smoking outside by you or your guests must be picked up and properly disposed of.

This provision (hopefully) serves to disuade this behavior, but also gives you a means to remediate and be compensated for it.

You can always issue a notice to cure to create a paper trail - this might also put pressure on the mother to curb the son's behavior, lest their lease not be renewed.  This is one of many reasons why I only offer MTM leases.