Lupita Sanchez is stuck in the one-bedroom apartment she shares with her husband, even though the plumbing is old, the place has cockroaches and it’s poorly maintained.

But the couple pays $1,200 a month for their Santa Ana unit, and that’s about as cheap as rent gets.

“You go somewhere else, they charge $200 more,” said Sanchez, 50.

Relief is not on the way.

Last year, asking rents for large-complex apartments in Orange County jumped 4.8 percent, according to a report from RealFacts, an apartment tracking service. And with vacancy rates low (5.2 percent), rents are likely to go nowhere but up.

Orange County apartment landlords were asking an average of $1,781 a month for vacant units in large apartment complexes in the fourth quarter, up $81 from a year ago to an all-time high, according to RealFacts.

“Asking” rent is the amount landlords were seeking for vacant units last quarter, not the amount existing tenants were paying.

The actual, or effective, rent averaged $1,648 a month, up $50 or 3.1 percent, according to a separate report last week by real estate data firm Reis. “Effective” rent is the amount landlords collected after subtracting concessions such as move-in discounts.

Those numbers made Orange County the nation’s seventh priciest rental market, ranking behind New York, San Francisco, Boston, Fairfield County, Conn., San Jose and Long Island. Nationally, the average rent is $1,124 a month, Reis reported.

Still, it’s cheaper to rent than it is to buy in Orange County. The median monthly mortgage for a home sold in December was $2,807, according to CoreLogic DataQuick, a figure that doesn’t include taxes or fees.

For tenants, the big difference between renting and buying means trying to figure out ways to cope with rent hikes.

In October, Sabina Suarez got a letter saying rent for her two-bedroom apartment in Fullerton would go up to $1,500 a month in February, an increase of $300 a month from what she’s paying now.

“I’m thinking to stay. But I have to see if I can afford it,” said Suarez, 65.

“If I can’t, I got to move somewhere else.”

Gary Emmert, who shares a one-bedroom unit in Santa Ana with his adult daughter, expects a hike sometime this year; it’s been two years since his last increase.

He paid $1,060 when he moved in 4 1/2 years ago. He now pays $1,185 a month.

“It’s hard for me because my income goes down,” said Emmert, 72, a retired elevator repairman.

“There’s nothing I can do about it. … I have to go ahead and pay it. It lessens money elsewhere.”

RealFacts records show rents have jumped in Orange County for four years. The hikes followed the recession, which pushed many people out of purchased homes and boosted the ranks of renter households.

The biggest increase last quarter was for three-bedroom townhomes, which were up $108 per month, to $2,736 a month, RealFacts figures show. That’s a gain of 4.1 percent from a year earlier.

The biggest increase on a percentage basis was for two-bedroom, one-bath apartments, which jumped 5.4 percent to $1,628 a month.

Newport Beach ($2,271 for apartments of all types) and Irvine ($2,085) continue to have Orange County’s highest asking rents of the 23 cities tracked in the RealFacts’ report.

Stanton (average rent of $1,356) continues to be Orange County’s most affordable city.

Tustin resident Hector Flores, 44, and his family pay $1,600 a month, just under his city’s average of $1,695 a month. Monthly rent for their two-bedroom unit has gone up about $100 in each of the past four years.

To make that up, the family has cut back on vacations and eating out. Still, Flores said it’s worth it to live in Orange County.

“We live in a safe place.”