MARYLAND'S LOW-INCOME housing market is headed into a crisis: Nearly half of 35,000 low-income units statewide may be lost in the next four years because their owners are thinking of quitting subsidy programs. Owners can make more money by charging market-rate rents, which are soaring, or by selling the buildings.

The result can be seen in Baltimore City: 43 percent of tenants with Section 8 vouchers cannot find qualifying apartments or landlords willing to accept them.

In coming months, the situation is only likely to grow worse as the pool of low- income housing shrinks.

"We simply don't have enough rental units, period," says Becky Sherblom of the Maryland Center for Community Development.

We don't begrudge building owners their desire to make money in the current market. Take a 46-unit townhouse apartment complex in Baltimore's Ridgely's Delight as an example. Twenty years ago, a partnership headed by C. William Struever enrolled it in a subsidy program. Having fulfilled its contract, the partnership wants out. It plans to sell the units, displacing its Section 8 tenants.

Hundreds of other Section 8 units throughout the metropolitan area are being removed from the inventory. Among these is West Baltimore's 900-unit Uplands Apartment complex. Meanwhile, many private landlords are paring down their low-end inventories because lead paint liability cases and problems in obtaining insurance have made their business too difficult.

This wasn't supposed to happen. In fact, about 10 years ago, when a bevy of subsidy contracts expired, most owners extended them because that was the thing to do in the economic conditions of the time.

This is not an attractive option now, due to a huge appreciation in property prices and spiraling rents in the open market.

There is no quick fix. The only long-term answer is more construction of low-income projects. And that, unfortunately, is unlikely to happen as long as all levels of government - from federal to state and local - are in the throes of budget squeezes.

Until more low-income housing becomes available, the social consequences could be devastating, Legal Aid Bureau representatives warn. Some families that lose their shelter may end up on the skids. Maryland is neglecting the coming crisis at its own peril because the consequences of dislocation are not going to be pretty: more poverty, hopelessness and crime.