For more than 25 years, Richard Johnson has called a one-bedroom apartment in Hayes Valley home — even as the neighborhood changed and rents increased, pushing out old friends. Johnson, 59, who was diagnosed with HIV in 1987, is disabled and receives a monthly rental assistance voucher from the Housing Opportunities for Persons with HIV/AIDS, known as HOPWA. “Next year, they could raise my rent to full market price, and I would lose my apartment of 25 years because I couldn’t afford it and have no way to fight an eviction,” said Johnson, who was able to get the rent increase reduced to 35 percent. “When you’re talking about renters who are long-term HIV survivors, these are people who are disproportionally low-income or on a fixed income,” Wiener said. The HIV/AIDS federal voucher program helps people living with the disease by providing rental subsidies. Residents must make less than 80 percent of the area median income, and the voucher will cover a certain percentage of the rent, up to $1,900. When rent becomes too expensive, many of those in the program are forced to leave the city, losing access to vital medical care and city services. “If they lose their current housing, there is very little chance of finding an affordable unit in the city again,” said Jaime Rush, a housing attorney for the AIDS Legal Referral Panel. [...] others, like me, have to face the cold fact that our landlords can raise our under-market-rate rental units to market rate in one increase.