If you're one of the more than 20 million American homeowners who use your real estate for two types of shelter -- tax shelter and physical shelter -- you've just been spared a lot of grief.

David Stockman's detailed set of options for limiting federal "tax expenditures" -- such as homeowners'mortgage interest deductions -- never made it into the final Reagan package, unveiled March 10.

Stockman, who servesas President Reagan's director of the Office of Management and Budget, declines to discuss how deep a series of cuts heconsidered in the home mortgage and consumer credit deduction areas. But top lobbyists here for both the National Association of Realtors and the National Association of Home Builders say they had good reason to be worried (until early last week) that Reagan might go along with Stockman's idea of capping mortgage interest deductions.

Homeowners' deductions of interest on their loans have exploded in recent years,thanks to inflation, high federal income-tax rates and highmortgage rates. The U.S. Treasury will "lose" $19.8 billion in incollected tax revenues this year because homeowners itemize and deduct their mortgage interest payment. Next year, according to estimates contained in a new Treasury Department study, the government will lose $25 billion. Just fouryears ago, by contrast, the annual revenue loss was estimated at less than $7 billion.

Add in the other tax preferences for homeowners and, in the words of one official at the Treasury, you get a huge, rapidly growing group of tax shelters "that will have to be controlled sooner or later":

$9 billion to $11 billion in homeowners' deductions of local property taxes.

$1.2 billion in nontaxation of homeowners' capital gains when they roll over their profits by buying more expensive houses.

About $650 million that Uncle Sam never sees because homeowners 55 years or older can keep up to$100,000 of their capital gains on sales of their residences tax-free.

$425 million in homeowner deductions due to energy-conservation credits.

Among the limits on homeownertax deductions reportedly considered by Stockman were ceilings on the amount any household could write off in a single year, and caps on the number of residences that could qualify for mortgage interest deductions.

Placing a $5,000 maximum annual limit on mortgage deductions, according to federal estimates, would produce a windfall of $4.3 billion in newrevenues to the Treasury. Placing a $10,000 limit on deductions would raise considerably less -- $800 million -- and a$20,000 ceiling would produce only about $100 million in new revenues.

The problem with the two lower limitations isthat they would affect a very large chunk of the country's taxpayers -- especially home buyers in the current high interest rate environment.

A $75,000 new mortgage at 15 percent, for example, generates over $11,000 the first year in interest deductions. That saves a home-buying couple in the 43 percent bracket (combined salary of $35,000 a year) about $4,700 in federal taxes.

Many home owners today factor those tax deductions into their calculations of the size and price range of what they can afford. Rising federal income-tax rates have turned two-worker families into tax-savvy consumers; they know that a 15 percent mortgage rate before taxes is an 8 1/2-percent, after-tax mortgage rate if they're inthe 43 percent bracket.

Trying to limit their deductionsin any way would amount to political suicide. The Reagan administration conceded this fact of life when it released its economic package minus Stockman's "tax expenditure" options.

Although there are still a few budget cutters on Capitol Hill who want to limit mortgage interest deductions (suchas Ohio's Democratic Rep. Don Pease, a member of the tax-writing Ways and Means Committee), the lack of support for theidea by Reagan dooms it at least for the coming two years.

The homeowner real-estate tax outlook, as a matter of fact, has now turned distinctly positive on Capital Hill. The federal tax rate on capital gains is likely to be decreased sometime this session, and legislation is being prepared that would even extend the $100,000 tax-free home-sale exemption to sellers in any age bracket.

Don't count on the latter making it through Congress this session. But as you fill out your 1980 tax return this weekend -- or think about getting your files together to do it next weekend -- you can rest easy that, at least through 1982, your real-estate deductions are safe from the grim reaper inside the Reagan administration.