DENVER -- A Boulder couple claims their landlord is wrongly discriminating against them by trying to get them to cover up while gardening.

Robert and Catharine Pierce said they have lived at 795 Cherry Ave. in Boulder for eight years.

During that time the couple has "sat on their porch and walked around" their yard wearing only thong underwear, plus pasties for Catharine Pierce, without any complaints, Robert Pierce said.

Until now.

Neighbors complained to police about the Pierces' scanty clothing. Police said the Pierces are not violating the law as long as their genitals are covered.

But their landlord, Boulder Housing Partners, has sent the Pierces a letter saying they could face eviction if they don't cover up.

BHP Executive Director Betsey Martens told 7NEWS the landlord and BHP try to "balance an individual's needs with the needs of the greater community."

The Pierces said the threat of eviction amounts to discrimination.

Neighbor Emily Hink said she spied Catharine Pierce, 51, gardening as she was driving home with her daughter, whose "jaw dropped."

Hink said she's not opposed to people being nude in their houses -- or even in a fenced-off back yard -- but the Pierces' home is on a corner just a couple of blocks from a school.

"There are so many parks around here, and there are lots of kids around," Hink said. "They're on the corner lot right across the street from the community gardens and the Waldorf school. The whole street is lined with kids."

Robert Pierce said he and his wife are advocates for the rights of children with disabilities and they would "never infringe on the rights of children."

BHP can choose to evict the Pierces if they continue their near-naked gardening.

If the couple fights the eviction, the municipal court would have to decide whether they are considered a nuisance.