It’s not an urban myth: an Upper West Side apartment that goes for $99 a week.

Dorothy Williamson, 70, a retired computer-systems administrator from Queens, checked into the Imperial Court Hotel at 79th Street and West End Avenue as a “tourist” in 2009 for a 10-day stay.

Two years later she’s still there, living as a permanent, rent-stabilized resident, paying $398 a month for a room in a classic pre-war building in one of Manhattan’s priciest neighborhoods.

All Williamson had to do was request a permanent lease.

The sweetheart deal comes courtesy of a little-known quirk in the city’s housing law that applies to the city’s 30,000 Single Room Occupancies, known as SROs.

“An individual can become a permanent tenant by simply requesting a lease,” said Marti Weithman, director of the SRO Law Project. “If someone comes in and pays for a night, he or she can request a lease orally, or in writing. The very act of requesting a lease gives you statutory tenancy.”

Once you’ve asked for the lease, you can’t be evicted.

“When these places are being used as a hotel, tourists don’t realize they have this option,” said Weithman. Anyone who stays in a room for 30 consecutive days automatically becomes a permanent resident.

An SRO building is a classification of affordable housing between an apartment building and a hotel. The buildings were established in the 1930s to supply temporary housing.

Today the majority of these buildings have been converted into budget hotels, many of which operate illegally because the buildings are in residential zones or are classified as dwellings for permanent residence.

Williamson rented a room for $59 a night at the Imperial Court in March, 2009, while looking for an apartment. The grand beaux-arts building operates illegally as a hotel, according to city records. As the $100-a-night peak tourist season approached, landlord Michael Edelstein wanted her out.

“I had paid for the hotel room through April 4, and he told me I needed to get out because they’d booked the room for someone else,” said Williamson, who was informed of her residency rights by lawyers at the SRO Law Project. “That’s when I gave him the lease request.”

Management called the cops the following day and tried to have her arrested, she said.

Williamson won her resulting lawsuit in civil court, where the judge ruled her rent should not exceed $99.52 weekly — the rent paid by the last permanent occupant of her room.

Her 200-square-foot carpeted room has a window overlooking 79th Street. She has a bed, a chair, a television, two refrigerators, a microwave and a hot plate She uses a communal bathroom in the hall.

“My room is nice for one person,” said Williamson. “But I went through a lot of stress.”

akarni@nypost.com

