A Calgary woman faces numerous charges after 89 cats were removed from a home in the West Hillhurst community and most of them euthanized.

The pets were suffering from a variety of health conditions and living in an unsafe environment, according to Brad Nichols of the Calgary Humane Society, who said subsequent vet testing revealed they were suffering from serious communicable diseases.

About two thirds of them had to be put down.

"It is uncommon to see such a volume of animals in a residential setting, even in a cattery," Nichols said, adding he's only seen three or four cases in his 12 years with the Calgary Humane Society where more than 90 animals were seized at once.

Calgary Humane Society peace officers responded to the home and removed the animals in April, but charges were just filed this week.

A 57-year-old woman is charged with permitting animals to be in distress, an offence under Alberta's Animal Protection Act.

She could face a maximum fine of $20,000 and a ban on owning pets.

Brad Nichols is senior manager of animal cruelty investigations with the Calgary Humane Society. (CBC)

"Charges were laid because of the conditions of the home and the condition of the animals, and the condition of the animals was quite bad," Nichols said.

"It is important that fanciers of any species know their limits concerning space, time and finances," he added. "Potential legal consequences aside, there have already been serious, irreversible consequences to the cats and the home."

And while most of the cats had to be put down, Nichols said it could have been worse.

"Generally, with a hoarding house, between feral behaviour and medical concerns, a very small proportion of them make it up to adoption," he said.

"Several dozen of the cats were able to be treated, rehabilitated and rehomed."