Who's that knocking at the door? It's the city of Gresham—trying to see how many pot plants are in the house.

Gresham city officials are threatening home searches and fines for citizens growing pot plants for other people in their residences.

Such "home grows" have been legal under Oregon's medical marijuana program for a decade. But Gresham banned them in May, and is now trying to require home inspections for people listed in the Oregon medical marijuana registry.

Documents show Gresham city officials demanded last month that at least one home grower allow city inspectors into her house—or the city will get a search warrant and issue fines starting at $5,000 a day.

Bear Wilner-Nugent, the homeowner's attorney, says that's an illegal overreach by Gresham City Hall.

"The city is claiming to be able to prohibit growers from doing what the Oregon Medical Marijuana Act specifically authorizes," Wilner-Nugent says. "In the 10 years since the legislature amended OMMA to authorize non-patients to produce marijuana for patients, no Oregon city has to my knowledge tried so hard to forbid that activity in citizens' private homes."

Gresham has been wary of marijuana legalization. This week, its city council banned early sales of marijuana to all adults in dispensaries.

"I am not willing to sell our community for a magic bag of beans or a bag of weed or whatever you want to call it," Gresham City Council President Jerry Hinton said Tuesday, according to The Oregonian. "It helps destroy lives and does not increase the quality of life for families."

The Aug. 28 letter shows Gresham has extended its crackdown on legal weed into homes.

"The purpose of this letter is to schedule an inspection to confirm that the medical marijuana grow site is a personal medical marijuana grow site that complies with city code," says the letter to a Gresham homeowner. "Thank you in advance for your cooperation."

The letter, written by Gresham senior code compliance inspector Rita Humphrey, says city officials want to make sure a medical-marijuana cardholder lives at the house and has no more than six plants. Both of these city restrictions are stricter than what the state requires.

The city's letter is here. Wilner-Nugent's written response is here. 

"Gresham is threatening to interfere with the private property rights of both the homeowners and the patients," Wilner-Nugent says. "It is doing so, moreover, in a way that directly conflicts with state law."

Humphrey has not yet returned WW's calls seeking comment.

UPDATE, 4:10 pm: City of Gresham spokesman Robin Franzen Parker says city inspectors are trying to keep weed businesses from being run in the house next door.

"The City's code aims to maintain neighborhood livability and prevent medical marijuana businesses from operating in residential neighborhoods," she says. "Our desire with respect to inspections is to always try to gain voluntary compliance without fines."