Rental vacancy rates have sunk to historic lows at the second-largest housing provider in B.C., another sign of the severe housing crunch facing the Lower Mainland.

Metro Vancouver Housing Corporation has reported an average vacancy rate this quarter of 0.44 per cent, below even the regional vacancy rate of 0.7 per cent.

Regional housing manager Don Littleford says the historic low vacancy rate is another indication that affordability problems have reached well beyond just low-income earners. Seventy per cent of MVHC tenants pay market rents.

"The emerging story is moderate income people, those that are up into the mid-$50,000 family income bracket, there's a real shortage of good, clean, decent family housing for people in that range," Littleford said.

It doesn't help that rental housing continues to be converted to condos. The most recent figures from the national housing agency, CMHC, show the region lost 637 rental suites in 2007 and 1,713 in 2006.

But developers haven't stepped up to replace the lost units with affordable rental housing.

"There's hardly any new rental housing being built because developers can't find a market for it," Littleford said.

"The rents would have to be so high before the developers made any money out of it as a rental property owner. They just look at the numbers and say, 'You can't do it.'"

Home-builders say tweaking federal tax laws on rental housing would be a significant step in drawing developers back into the rental housing game.

Decades-old changes to how income from rental housing is treated, for example, have reduced the attractiveness of rental investment, according to the Canadian Home Builders Association.

Civic politicians, in the middle of their own election campaign, have long begged the federal government for help.

"It's a huge issue at every income level," said Vancouver Coun. and NPA mayoral candidate Peter Ladner. "There's pretty widespread agreement that if we were to change the federal tax laws you'd get the private sector back into housing."

Vancouver-East NDP MP Libby Davies says housing should be the number one issue in the federal election as well as the pending civic and provincial campaigns.

"The federal government is really the great gaping hole at this point," Davies said. "The province has been doing some stuff. The City of Vancouver has always done a good job on housing. But without the resources of the federal government, there is a huge, gaping black hole in terms of building housing capacity."

Irwin Loy writes for 24 hours.