There is a housing shortage that is helping pad savvy real estate investors' pockets. If you have college-age children you may be well aware that housing for students is in great demand.

Michael Zaransky, author of "Profit by Investing in Student Housing," says that more than 80 million people will turn 18 over the next decade, which is part of the reason for the school-housing demand. Also adding to the need for more housing is the fact that more young people are going to college. And the final factor, "Public universities are under severe financial constraints so as a result they don't have the ability to build more dorm rooms and because of that they're relying on the private sector to house students," says Zaransky.

His book details how to break into this lucrative market that has often been overlooked by investors. Zaransky shared five tips with me on how to get started, what to look for in housing, and what to avoid.

Invest in university-owned low bed-to-student ratio areas.

This is a critical factor for obvious reasons -- students need a place to live while attending college. According to Zaransky, on average, nationwide, school-owned housing capacity is only about 30 percent of the total enrolled student population. That leaves approximately 70 percent of students needing to find alternative housing.

You can start with just $20,000.

Zaransky recommends starting out with a condominium in the $150,000 to $200,000 range and renting it out to students. "What is unique about the student housing investments versus some traditional ones is that rents are relatively high closer to campus and occupancies are frequently 100 percent with no vacancy. So that, as a result from a cash flow standpoint, very often the cash flow yields positively, even after debt services at today's interest rates, from day one," he says.

Look in High-growth states.

High-growth states drive demand for student housing. It makes sense that large population states will likely see greater growth in enrollment, which translates to a need for student housing. States such as California, Florida, Texas, and Arizona have the greatest enrollment in colleges and demand for student housing. "California leads the country in terms of its ranking of the number of people who are expected to turn 18 over the next 10 years," says Zaransky.