Emily Seru and her husband — both first-time home buyers in 2005 — bought their three-bedroom, $174,000 house in St. Paul's Frogtown neighborhood 10 years ago.

"Everything else we were looking at was over $200,000 in the city," she said. "And so we bought the house, we were really happy, and then the market crashed."

The home across the street fell into foreclosure and disrepair, Seru said, as did many others in the Frogtown neighborhood, where the median annual income is just $33,000.

Seru said she was fortunate to keep her job during the recession, and the family never missed a mortgage payment. Nevertheless, she said, it's frustrating to look at their annual county tax assessment and see how their home's value has plummeted.

"Since we bought our house 10 years ago, it's now worth about $102,000," Seru said. "We owe $139,000 on it."

Despite an improving housing market, many Twin Cities homeowners still owe more on their properties than they are worth. By one measure, more than 15 percent of mortgages — most often in areas the housing recovery has left behind — remain under water.

Seru said she was able to refinance her mortgage and lower her monthy payments. But a 41 percent loss in property value put her deep in the home equity hole. She can't easily get a home equity loan to make repairs — which has become a big concern for a 127-year-old house.

"Because we don't have any equity in the house, we can't really afford to do much to it, and that worries us," she said. "How long can we let a crack in the window go? When will we need to get a new roof?"

Seru and her family are not alone. More than 107,000 Twin Cities mortgages are under water, according to Zillow, a real estate data company. That's 15.5 percent of all Twin Cities mortgages. Still, the figure is much improved from 2012, when negative equity in the metro peaked at 39.9 percent.

Zillow economist Svenja Gudell compared her company's information on home values to mortgage data from TransUnion, a credit rating agency. Gudell said she found that neighborhoods hit hardest by the housing bust are places where the biggest share of underwater mortgages still exist.

"If you separate the market into tiers and you look at the bottom third, most of the negative equity sits in that bottom third," Gudell said. "And the double whammy for homeowners in the bottom third is really that not only are they more likely to be under water, but they're also likely to be very deeply under water."

Gudell said that, ideally, the negative equity rate should be no more than 5 percent. She said all underwater mortgages are a drag on the market, because many people who may want to sell simply can't.

Melissa Maier — who lives in the Payne-Phalen neighborhood on the east side of St. Paul — said she's about $70,000 under water. For her, being unable to sell her property means being a landlord — a role she does not relish. Seeking a bigger yard, she bought her current home back in 2008. But as the market tanked, Maier was unable to sell her previous home a mile and a half away. She listed it several times, but said she never got any serious offers.

Maier said finding renters hasn't been too difficult, but the cash coming in just barely covers her mortgage. Dealing with tenants has been a hassle, she said, and the upkeep for a rental home is expensive.

"This year I took a big loss, because I had to replace some doors — the garage doors, the front doors — and a new boiler," she said. "So it was a huge loss. That one will take a while to recover from."

In the meantime, Maier said she'll continue to make payments on the house, building her equity bit by bit with the hope that she can sell it one day. But she knows it will be a while.

"I'm thinking I'm in it for the long haul," she said. "I don't think it's going to be in the near future."

Still, there is some encouraging news in Zillow's report: While negative equity is on the rise in a number of communities, the rate of underwater mortgages here in the Twin Cities continues to tick downward.

And even in the bottom tier of the area's housing market, Gudell, the economist, said she is starting to see small increases in home values.