Hundreds of volunteers are pounding the pavements in Metro Vancouver trying to find and count the number of people in the region who are homeless.

The survey is held every three years, covering municipalities from West Vancouver to Langley. Nearly 1,200 volunteers count and survey people staying on the streets and in shelters over a 24-hour period.

City staff, service planners and community groups use the numbers to get a sense of the homeless population in their municipality, so they can make informed decisions about funding and services for those living without a fixed address.

Jill Atkey, CEO of the B.C. Non-Profit Housing Association, said the volunteers are asking people what services they have been accessing while experiencing homelessness.

Atkey said the last Metro Vancouver count, done in 2017, showed the top three services used included emergency rooms, meal programs and ambulance transportation.

"Those are significant costs," said Atkey on The Early Edition Wednesday. "It costs a lot to manage homelessness."

The data can also be compared to previous years' to see how the homeless population is changing and whether those changes are in or out of line with previous trends.

The 2017 count found the number of people living without a fixed address had risen 30 per cent over the previous three years.

Atkey said that count registered an increase in the number of seniors and young people living on the streets, as well as the number of people holding down full or part-time jobs who still cannot afford housing.

In total, 3,605 people were found to be without a permanent home in the region in 2017. More than three-quarters of those people were in Vancouver and Surrey, though smaller communities like Delta and White Rock also saw an increase.

Organizers have long said the numbers are not a perfect representation of the homeless population. Atkey said officials are aware the count underestimates the actual size of the population.

"At the end of the day, it's a fairly severe undercount," Atkey said in an interview Monday.

"There are lots of people experiencing homelessness throughout the province that are couch-surfing or temporarily in shelters but don't have adequate access to safe affordable homes, so they get missed in the count."

Atkey said the questionnaire is "robust," asking people questions as to how long they have lived without a permanent home and what kind of services they would like offered.

The City of Vancouver organizes its own annual homeless count, though it folds its results into the regionwide survey on years the Metro Vancouver survey is conducted.

The Fraser Valley Regional District will also be conducting its own homeless count Tuesday night and into Wednesday.

The region's count in 2017 found the homeless population in the Fraser Valley was growing faster than that in Metro Vancouver.

According to Atkey, initial results from the count should be available in May and a more in-depth report can be expected later in the summer.