More married couples are living with roommates to save on the cost of housing

More and more married couples are bringing a third person into their homes. In many cases, it seems to be because they need help paying the bills.

Real estate website Trulia used data from the U.S Census Bureau, collected between 1995 and 2018, to analyze "where married couples are more likely to take on roommates" and "what could be driving the rise of this phenomenon."

Overall, only a small fraction of married households actually included a non-related roommate. Still, the arrangement has "become far more common over the past two decades," according to the report. In 2018, 0.46 percent of all married households, or about 280,000, included a roommate. That's compared to its historical average of 0.36 percent and "more than double the rate observed in 1995 (the earliest year for which data is available)."

The trend seems to have caught on most on the West Coast, where housing prices can be particularly expensive: Of Trulia's top five cities with the largest share of married couples living with roommates, four are in California.

Here's how the top five cities stack up:

Share of married-with-roommate households (2012-2016): 2.31
Percent change in share of married-with-roommate households (2005-2009 to 2012-2016): 78.2
Median home price (2012-2016 average): $522,815
Share of income needed for a median home (2012-2016 average): 34.1

Share of married-with-roommate households (2012-2016): 2.06
Percent change in share of married-with-roommate households (2005-2009 to 2012-2016): 4.8
Median home price (2012-2016 average): $631,387
Share of income needed for a median home (2012-2016 average): 43.9

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Share of married-with-roommate households (2012-2016): 1.89
Percent change in share of married-with-roommate households (2005-2009 to 2012-2016): 39
Median home price (2012-2016 average): $929,093
Share of income needed for a median home (2012-2016 average): 52.6

Share of married-with-roommate households (2012-2016): 1.69
Percent change in share of married-with-roommate households (2005-2009 to 2012-2016): 27.6
Median home price (2012-2016 average): $548,225
Share of income needed for a median home (2012-2016 average): 38.8

Share of married-with-roommate households (2012-2016): 1.64
Percent change in share of married-with-roommate households (2005-2009 to 2012-2016): 27.7
Median home price (2012-2016 average): $716,541
Share of income needed for a median home (2012-2016 average): 38.8

In markets with the highest rates of married couples living with roommates, the share is "between four and five times the national rate," the report explains.

On average, "every $100,000 increase in the median metro home value corresponds to a 0.25 percentage increase in the share of married couples with roommates," the report notes. And "while correlation is not causation, it's notable that as housing costs have risen in many of these expensive markets, the share of married-with-roommate households has, too."

In pricey Honolulu, the rate nearly doubled, jumping from 1.29 percent in 2009 to 2.31 percent in 2016.

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While renters are often "subject to fluctuations in the cost of housing during their tenancy or when they move, homeowners tend to stay in one home for longer and their cost of housing is usually stable, having been determined when they bought the home," says Trulia.

So "married homeowners are less likely to bring on roommates when faced with escalating housing costs than married renters."

The share of married homeowners with roommates peaked in 2012 around the same time as the national foreclosure crisis, which "suggests married homeowners were more likely to bring on roommates after the roommate may have experienced financial distress," and not necessarily the other way around.

The share of married renters with roommates went up in 2012, but it also went up in 2007 when housing affordability was at its worst. This suggests that "roommates also played an important role in mitigating the housing costs of married renters."

This data highlights the "nexus between housing affordability and the presence of a roommate in married couples' homes." And while "most married couples will continue to nest alone or only with family members," the research predicts, it's clear "roommates often allow couples to better manage the vagaries of the housing market (and it is certainly beneficial for the roommates)."

While some Americans take on roommates to save on the cost of housing, others opt for more extreme measures: Desperate residents of the Bay Area have resorted to living in "crappy old storage rooms" that have been converted into apartments, for example, while others downsize and sleep in their cars.

And more and more workers are becoming "super-commuters," who must travel more than 90 minutes just to get to work, since homes in exurbs or other areas far from their jobs are all they can afford. Danny Finlay, a 30-year-old account executive in San Francisco, travels four hours and 140 miles every day from Dixon, California, to avoid exorbitant housing costs.

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