Paying the rent just keeps getting tougher for Michelle McLaughlin, one among thousands of Clark County renters faced with a rate hike this year.At $699 per month, her rent is fairly low for a two-bedroom apartment in Vancouver’s Orchards area, she admits. But it’s about to nudge higher, said McLaughlin, who received notice of a $20 increase this month. She also just learned her $250 pet deposit is no longer refundable.It’s been less than a year since she and her 18-year-old daughter, Cora Hall, moved into the apartment, one of 334 units at Meadow Wood Apartments, a sprawling complex on the east side of Northeast 121st Avenue. Now, it has gotten to the point where McLaughlin, 42, dreads the newsletters that arrive in her mailbox from Meadow Wood’s management.“They say, ‘friendly reminder,’ but they are anything but friendly,” said McLaughlin, a compliance clerk for Evergreen School District’s special education department.Her experience is not unusual. Housing experts say rent concessions are all but nonexistent as the supply of rental units tightens in Portland and its suburbs. Local rents are expected to rise through the year, pushed by Vancouver’s low vacancy rate of 3.6 percent and the Portland metro area’s overall vacancy rate of 2.5 percent.The metro area rate is low compared with other West Coast cities, according to a survey released in February by the National Association of Realtors.Portland tied with Minneapolis for the second-lowest rate in the nation, coming in just behind New York City’s 1.8 percent rate. All three cities were well below the national average of 4.7 percent.