Evelyn McAllister's rent in the Twin Towers apartment in Silver Spring will go up to $412 next month, a $50 increase over the amount she is paying now and more than double the rent she paid when she moved in 11 years ago. McAllister is 69, has diabetes and heart ailments, and said she doesn't know "how I'll be able to afford" the rent.

Theresa Goldberg, 83, is paying $300 a month for her efficiency apartment, after a recent $62 increase. She said she lives on a small fixed income and doesn't "understand why" her rent is raised every year. She has lived in the Summit Hills complex in Silver Spring for 17 years.

Rents have risen steadily in Montgomery County since the removal of rent controls in January 1981. Many landlords have followed the voluntary guidelines that replaced the legislation. The guidelines call for increases of not more than 15 percent in older buildings and 10 percent on newer apartments a year.

But some of the increases have come in large chunks and hit handicapped and elderly residents who are most vulnerable. Like McAllister and Goldberg, many of these tenants have lived for years in the same low-rental apartments.

Despite complaints from some renters, though, tenants have few champions and rent control has no fans among the candidates for county offices in next month's general election.

Housing is an issue that all the local candidates are addressing -- but no one this year is saying what tenant groups would like to hear. Neither incumbent County Executive Charles W. Gilchrist nor GOP challenger Joseph C. McGrath supports a return to rent control, or rent stabilization. Both agree that controls are a disincentive to developers.

When the rent control question is posed at forums and debates -- and inevitably there is a rent control question -- Gilchrist will talk about how the county had more new housing starts this year than anywhere else in the area. He also points out that the vast majority of rent increases were at or below the county guidelines.

McGrath, on the other hand, will always tell audiences that he is a tenant. He lives at the Falkland Apartments in Silver Spring, and served as president of the tenants association. He will tell audiences that his own rent went well above the guidelines, as proof that Gilchrist is not using his office to "jawbone" landlords into keeping rents low.

McGrath also says that as a banker, he can put together creative financing packages and tax breaks to lure more housing developers to the county.

Montgomery's Office of Landlord-Tenant Affairs monitors rent increases, which landlords are required to report, and is consistently upbeat in its announcements. In his third-quarter rent increase report to the County Council, Executive Director Richard J. Ferrara pointed out that 96 percent of the rent increases were below 15 percent, saying, "we are encouraged by the overall declining trend and by the drop in increases over 15 percent."

But the report also acknowledged that 240 hikes of more than 15 percent were recorded in the third quarter, many hovering around 20 percent, a few around 35 percent and one of 81 percent. Most were imposed in three Silver Spring complexes -- Summit Hills, University Manor and Quebec Terrace -- plus the Promenade in Bethesda.

Ferrara noted that in several buildings, the steep rent increases were handed out by new owners, who are paying high interest rates on their purchase money, and have undertaken extensive renovation.

Summit Hills, a 1,120-unit complex, is a dramatic example. Rent increases have been as high as 35 percent and more. Tenant Joseph Levin said his rent went up by 86 percent in two raises 12 months apart. Levin and his wife, Betty, now pay $844 for the large, three-bedroom apartment they have lived in 13 years.

In April 1981, the Summit Hills owner, Central Management Co., told Levin his rent would be raised from $580 to $900 monthly. Levin fired off letters to County Executive Gilchrist, members of Congress from Maryland and journalists. A compromise resulted, and the increase was reduced to $754. His second raise, to $844, came last spring.

Levin concedes that the market value of his apartment may well be $844, but says that the "sudden big increases" are unsettling to others. "Many of the residents here are widows, many were here when the building first opened up," he said. Levin feels that without rent control laws, "you're at the mercy of the landlord. There's nothing that can make them not raise the rent. The landlord-tenant office goes through the motions" of trying to persuade owners not to raise rents unreasonably, but is not effective, he said.

Other tenants worry that annual rent increases of 10 or 15 percent will soon push the cost of their apartments beyond their reach. Summit Hills resident Isabel Senft has lived in the complex 20 years and now pays $390 for her apartment. She said her 73-year-old husband must work as a waiter because the couple cannot live on their Social Security income.

David Hillman, one of the owners of Central Management, said the firm lowered the rent increases of about 100 units after tenants said they could not afford to pay them. He said his company is "losing money" on Summit Hills because of high interest rates on the mortgage and the expense of extensive renovation. Residents concede that conditions have improved in the run-down, troubled complex of apartments since Central Management purchased it three years ago.

High interest rates and high costs of rehabilitation have also meant higher costs for tenants of the Quebec Terrace Apartments. Rent increases on the 125 units have averaged 26 percent, with some up to 32 percent, as new owners sought to correct numerous housing code violations, according to the landlord-tenant office.

The report said three other once run-down complexes are raising rents to help cover costs of high interest mortgages and extensive repairs made by new owners.

"This is a dilemma that we are constantly presented with when dealing with old properties in declining areas in need of extensive repairs," said landlord-tenant office director Ferrara in his report.

He said similar experiences can be expected at several other apartment buildings, including Long Branch, Goodacre and Flower Branch if they are sold. A spokeswoman in the landlord-tenant office said these buildings "are being eyed" for purchase.

Low-income tenants in these complexes will be displaced unless they receive extensive subsidies from the county, Ferrara's report said. These residents are eligible for help from Hardship Rental Assistance, a program established to help them cope with rent increases that came with the end of rent control laws. The county pays for increases over the 10 percent level, up to $75 per month. About 1,700 persons are receiving help under this program, 40 percent of them over 62. In addition, five other rental housing assistance programs are available in Montgomery.

Trouble of a different kind means 35 percent rent increases in December for 28 of the tenants at the 816-apartment Willoughby in Chevy Chase.

The Willoughby is in the process of condominium conversion, with more than half of its units already sold. Until sales contracts on all the units have been signed with the converter, First Condominium Development Co., and the conversion is complete, Willoughby owner Milton Barlo said he receives rent for all the units. But the state has assessed the building as a condominium, which meant a tax increase of more than half a million dollars, bringing the total to $899,575.

Barlo plans to pass along much of this cost to the tenants. He said all will receive 35 percent rent increases when their annual contracts are renewed.

Willoughby tenant Geraldine Quinto, a Montgomery County junior high teacher, said she cannot long afford to pay the $660 a month her one-bedroom apartment will cost and is looking for a new apartment.

A number of condominium conversion projects have stalled because of the recession and competition for the remaining buyers. Many of these conversions began at about the same time about two years ago, said Nikki McCausland, chief of landlord-tenant relations for Montgomery. About a third of the county's estimated 17,000 condominium units are being rented out by their owners.

"There's rental stock still available, but in a different form, at condominiums," she said.

An overall vacancy rate of around 5 percent in the county also will help keep a lid on most rents, she believes.