Interested in renting a house or apartment for your next vacation, but nervous about dealing with total strangers in a rent-by-owner arrangement or a big agency? Don’t despair. According to a new PhoCusWright study of the vacation rental market, there are 1.26 million homes available for short-term rental in the U.S. alone and–here’s the interesting thing–about a quarter of those are rented out on a casual basis. In other words, they don’t show up in home rental directories and websites.

So how do you find out about them?

In many cases, the owners rent them out only to friends, acquaintances, friends-of-friends and relatives. So if you’re interested in staying in a chalet in Vail, a cottage in the Muskokas or a villa in Tuscany, get the word out among your social network.

Ah, I hear you say, “I don’t know anyone who owns a second home.”

Don’t be so sure. Once you start (discreetly!) letting it be known that you’d like to rent a vacation property, you may well be surprised. Where I live in Ontario, for instance, few people don’t know someone–a neighbour, a business colleague, a cousin–with some sort of stake in a nearby lakeside cottage. And don’t forget that it’s not just who you know, it’s also who your friends know. Six degrees of separation can take you a long way from home.

Of course, not everyone who owns a second home is keen to rent it out. Also, not everyone wants to rent to just anyone. Many people will be justifiably nervous of casual acquaintances who are overly pushy about their desire to move into their foreign pied-a-terre.

And while there are many advantages to renting from someone you know, there are also particular pitfalls. What happens to your relationship, for instance, if the house’s microwave breaks down on your watch?

All of this being said, many people with second homes are eager to earn a little extra income from them when they are not in residence. And a private rental from a friend can be the perfect way to get your feet wet in the vacation rental market. Just approach it as you would a rental from a stranger, complete with written contracts and the understanding that this is a business arrangement.