An effort to raise the income eligibility for below-market-rate housing in San Francisco appears to have failed Tuesday.

Proposition U, which required more than 50 percent of the votes to pass, would have increased the income eligibility limit for on-site rental units in all new and existing below-market-rate housing to up to at 30 percent of the household’s total income, provided the household earned no more than 110 percent of the area median income.

Opponents, while supportive of subsidized middle-income housing, had said there are already steps in place to build middle-income units.

Additionally, opponents said Prop. U would have allowed landlords to raise the rent of a unit offered at, say, 50 percent of the AMI to 110 percent of the AMI once a resident moves out.

Supporters had countered the measure will affect just 2 percent of new homes built in San Francisco.