The City of Ottawa is dealing with an influx of reports of rats, but the cause of the rodent increase isn't known.

Between May 1 and June 20 this year, the city received 157 complaints about rats, compared to 84 such reports during the same period in 2018.

Since the beginning of the year, residents have filed 268 complaints about rats on private property.

To compare, there were 328 complaints in all of 2018, according to the city's bylaw department.

The rodents have been particularly prominent in Rideau-Vanier and Rideau-Rockcliffe, where there were 47 and 13 complaints to the city, respectively, between May 1 and June 20.

During the same time last year, Rideau-Vanier residents complained about rats 26 times, while there was only one complaint from a resident in Rideau-Rockcliffe.

Spring floods could be partly to blame

"Ever since [city crews] started doing the sewers in Vanier, the number of rats that are roaming around has increased," said resident Navid Fadaie.

He was working on a project where a home was demolished and some rats ran out, he said. He's concerned for his children who often play outside and wants the city to take care of the infestation.

The rat population may have been affected by the recent floods, said Rideau-Rockcliffe Coun. Rawlson King. He pointed out that construction, road and sewer projects and abandoned houses can also play a role.

"These issues aren't just the pests themselves, but it's also issues of refuse in garbage and other things that attract rats," he said.

Coun. Rawlson King says problems with rats can happen when city crews are working on roads or sewers. (Jean Delisle/CBC)

The statistics relate to all calls about rats, which could be anything from a wounded rat to residents worried that garbage or debris could attract pests, wrote Alison Sandor, a spokesperson for the bylaw department, in a statement.

Furthermore, some of the complaints overlapped and not all of them were confirmed after an investigation, she wrote.

Homeowners face violation notice

When the city receives a complaint, workers inspect properties where rats were reported. The city could give the owner a violation notice and require the person to take care of the infestation.

Notices may require the owner make repairs to prevent the presence of rats, or ask to cut tall grass or remove waste that could attract unwanted rodents.

The city also has a duty to intervene if rats use public infrastructure, such as sewers, to travel or as a den.

The situation can get tricky when rats are discovered underground. Even though the city can set bait, it can't put that bait in a single water or storm sewer because the bait could be rejected or have a negative environmental impact, said Sandor.

However, she said the city has never struggled with a major rat problem in its sewers.

Ottawa Public Health provides advice on a five-step process for getting rid of rats that includes looking for evidence by checking for burrows or nests, cleaning up property and making sure garbage cans are securely sealed.