Waimanalo residents Rich and Bobbie Ubersax received a letter from the city this week telling them to stop advertising an illegal vacation rental.

Except the couple have never rented their beachfront house — either as a legal, long-term unit or illegal short-term vacation rental — in the 16 years they’ve owned it, much less put out a rental ad for it.

The house has a guest bedroom above the garage that would make an ideal rental, Rich Ubersax said. “But it has only been used by family or friends, and never at a charge,” he said. “Based on the letter’s content, it seems the city is on a fishing expedition.”

The Department of Planning and Permitting received 390 complaints from Wednesday to Friday after sending out about 5,000 “courtesy letters” reminding people about the new law taking effect Thursday that levies strict fines for advertising illegal vacation rentals.

Short-term rentals of less than 30 days are illegal in residential neighborhoods unless specifically permitted, and the city has not approved any permits since 1989, although it will begin issuing about 1,700 permits for hosted vacation rentals starting in October 2020.

All the complaints came from people who said they had received the letters in error, said Kathy Sokugawa, acting DPP director.

The Honolulu Star-Advertiser heard from more than a dozen upset homeowners — from Kaimuki to Makakilo, Hawaii Kai to the North Shore — all complaining they got the letters by mistake or felt they were either being harassed or being pressured to turn in neighbors who are operating illegally.

The letters each list the property’s address, the advertised per-night rate, how many bedrooms are available and how many guests are allowed.

The letters all state, in part, “Our preliminary investigation revealed that the above property or ones close to it may be involved in short-term renting and advertising. You may not be directly involved in this commercial activity; perhaps it is a tenant. In any event, the law says the fee owner is ultimately accountable, including advertising the home as available for short-term renting.”

The letters go on to say, “If this is not your property, we ask that you contact us, particularly if you can identify which property is involved.”

Sokugawa, in an email Friday, said those who received letters were not picked at random, but by looking at “drop pins” appearing on online platforms to indicate rental locations.

“We did not mail letters regarding properties where there is no suspected activity,” Sokugawa said. “Stated another way, we mailed letters to the property based on the drop pins used in the ads.”

She acknowledged there may have been errors. “If the drop pins were not exact, this may have resulted in property owners receiving a letter even though they are not renting short term.”

DPP is “learning from the complaints on how we can improve our search for potential illegal operations,” Sokugawa said. “More importantly, we believe the letters are already reducing the advertisement activity levels, which means an immediate reduction in the actual number of housing units available for short-term rentals.”

Missy Maii rents her Kaimuki house to a long-term renter and was surprised to receive one of the letters addressed to the Hawaii Kai home where she lives. “I have never and will never vacation-rent my home or rooms in my home to anyone,” Maii said.

She said she wants to know which website listed information about her property. “I feel I have a right to know what site my house was on and who posted my house. It’s scary to me that they have all this false information about my house.”

Brian Neff, who lives along Mokapu Boulevard in Kailua, also received a letter suggesting he advertises an illegal rental. “You can put me on record as being very, very (angry) about the city falsely accusing me of this,” he said.

“I also do not know of any short-term rentals.”

A Kaaawa woman, who asked not to be identified for fear of retribution by the city, also received a letter.

“The thing that I’m really upset about is that we are guilty until we prove we’re innocent, unless we rat out our neighbors,” the woman said.

“They’re using old information to make their case instead of checking,” she said. “Now I have to make the extra effort to prove that’s not me because they are too lazy to check.”

Sokugawa said a lot more research will be done before issuing violation notices when enforcement begins Thursday. Those found to be in violation will be served a notice of violation, and the person running an illegal ad will have seven days to remove it. If the ad remains after that, a notice of order will be issued, and daily fines of $1,000 to $10,000 will begin accruing.

“We will need to be, and will be, more methodical and accurate in acquiring irrefutable evidence of short-term rental activity before issuing a (notice of violation) and are committed to doing so.”

So people receiving letters in error needn’t worry if they aren’t running an illegal ad or operating an illegal rental, she said.

“The recent letters begin a conversation between the department and neighborhoods about short-term rentals,” Sokugawa said. “They are not a precursor step to getting (a notice of violation) and (notice of order). One should not assume that getting a letter recently from DPP means you will get (a notice of violation).”

This is the first time the city is targeting advertisements as a zoning violation, Sokugawa said.

“We are coupling this new endeavor with more technology-based investigations. Instead of manually visiting each website by an inspector sitting at a computer terminal, we are developing the ability to conduct online sweeps” that will make it easier to gather information more quickly and save many hours of staff time, she said.

But the complaints show there’s a need for improvement, Sokugawa added. “We should do a better job to more accurately focus our attention and not unduly stress residents,” she said. “We need to refine our processes and are already doing so.”

One man who emailed the Star-Advertiser said he wasn’t upset after receiving a letter even though he doesn’t own a vacation rental. “I am happy to see that the mayor is cracking down on short-term rentals,” he said. “It should have been done long ago.”

For more information on the city’s new vacation rental law, go to honolulu.gov/dppstr.