The city of Portland is surveying landlords in an attempt to better understand a rental market that continues to fuel calls for tenant protections and more affordable housing.

A short survey composed of six questions has been sent to 2,600 landlords in Maine’s largest city. The results will be presented later this year to the City Council’s Housing Committee, which ordered the survey.

It’s the first time the city has surveyed landlords about the rental market, officials said.

“We encourage property owners to respond to this survey to help us understand the market for rental housing in the city,” City Councilor and Housing Committee Chairwoman Jill Duson said in a written statement Friday.

Portland’s housing market has been a source of concern in recent years, in terms of safety, affordability and supply.

In 2015, a Maine Sunday Telegram analysis found that rents had increased by 40 percent in the preceding five years, primarily because of an increase in demand for a limited amount of apartments.

In recent years, rents have stabilized as hundreds of new units have been added to the housing market. But much of the development has been market-rate and luxury apartments and condominiums, rather than units that are affordable for city workers, including those who work in coffee shops and restaurants.

On Thursday, the nonprofit housing provider Avesta Housing released a report showing a nearly 24 percent increase in requests for affordable housing in the last four years, from 3,067 in 2014 to 3,789 in 2017. However, a lack of turnover in units and scarce resources to build new units have kept new household move-ins relatively flat, from 340 in 2014 to 393 in 2017, it said.

The rental market is also making it difficult for low-income families to remain in the city, where they can receive services and work, and has spurred calls for tenant protections and rent controls.

Although voters last November turned down a citizen-led effort to adopt a form of rent control in Portland, Mayor Ethan Strimling on Wednesday called on the City Council to revisit that proposal to see if there were any components that should be adopted to better protect renters.

Housing was a major focus on Strimling’s third State of the City address. He asked the council to reconsider other tenant protections that had been turned down by previous councils, including requiring a 90-day notice for evictions, rather than 30 days, and requiring landlords to accept housing vouchers, a program that is currently voluntary.

Strimling also called on the city to dedicate $10 million by the end of 2019 to affordable housing projects, half of which would be funded by a bond.

The council’s Housing Committee decided to survey landlords about the rental market after being presented with a housing report from city staff last October. The committee “realized it was difficult to find a resource with local rental market data,” the city said in a news release Friday.

The survey is being sent to landlords currently listed on the city’s registry. It asks landlords about the number and types of rental units; whether there are any tenants whose rent is funded by a housing voucher; the rents charged and square footage of units; the number of people living there; which utilities – if any – are included with the rent; and the condition of the building.

Maine-based 45 North Research LLC has been hired to conduct the survey. The firm, formed in 2016, is led by two former state economists, Michael LeVert and Catherine “Kate” Reilly deLutio. They will be paid $14,250, according to the city.

City Hall Communications Director Jessica Grondin said the city hopes to have a final report from the consultant in March or April.