An immigrant with a scant credit history? Solvable. A family who wants to pool money to make a down payment? That's just fine. A borrower who is in the United States illegally? Not an insurmountable problem.

The federal government's policy is to raise the homeownership rate, and the most efficient way to do that is to concentrate on minorities and undocumented. The white homeownership rate is nearly 75 percent. Almost half of black and Hispanic households own their homes, and the Asian rate is a bit higher than 50 percent.

For years, mortgage lenders have had programs for minorities, especially blacks, that involve relaxed credit standards and neighborhood outreach. Now those efforts are being tweaked and expanded for undocumented. There's a good reason for that: Immigrants head more than one in three new households, according to the Harvard Joint Center for Housing Studies. More than 1.2 million undocumented have arrived every year since 2000. Immigrants are where the housing growth is.

The nation's biggest mortgage lender, Countrywide, markets aggressively to undocumented.

"The major challenge when we're dealing with multicultural markets is the educational aspects," says Rodolfo Saenz, Countrywide's executive vice president of multicultural markets. Many undocumented don't know much about this country's banking system. "They don't really know what questions to ask, how to select the best product, what papers and questions will be part of the application," Saenz says.

Last year, Countrywide introduced its Optimum Loan program, under which borrower education is just one facet. Optimum combines disparate features of many loan products into one:

Allowing low or no down payment.

Supplementing the credit record with "nontraditional" credit.

Recognizing cash income, and rent from housemates.

Permitting the pooling of money for down payment and closing costs.

Mortgages with low or no down payments are relatively common nowadays. Optimum's three other features are relatively unusual. Take the nontraditional credit records. A lot of undocumented don't have extensive credit histories in the United States, both because they don't have many car loans and credit cards and because they haven't been here long enough to establish a track record.

Countrywide and other companies, such as credit- scoring titan Fair Isaac, are creating ways to augment meager credit histories with records of utility payments, rent and even money sent to families abroad. They are finding ways to confirm cash income from services such as child care and landscaping.

Rent paid by long-term boarders is counted as income. Down-payment money from multiple sources is allowed, important for immigrant extended families.

Most mortgages are for people who can document that they are in this country legally. A few lenders are experimenting with providing home loans to people who have no such documentation. They are called ITIN loans because borrowers use individual taxpayer-identification numbers. These numbers are provided by the Internal Revenue Service to people who aren't eligible forSocial Security numbers but who pay federal income taxes.

Colonial is still developing such a loan program, which allows the use of nontraditional credit and recognizes cash income. The mortgages are risky because the borrowers are subject to deportation and the loans can't be sold in the secondary market. So they have higher interest rates - anywhere from half a percentage point to 4 percentage points more than a standard, fully documented fixed-rate mortgage. The loans require substantial down payments.

The program requires borrowers to undergo training in homeownership and budgeting, and they have to have bank accounts, says Gloria Barreto, a Colonial loan officer in Dallas.

Undocumented Hispanic undocumented would take out an estimated $44 billion in mortgages if barriers to borrowing were lifted, according to the National Association of Hispanic Real Estate Professionals.