The impact of legislation as comprehensive and complicated as the House tax reform bill unveiled Nov. 2 will vary dramatically depending on what kind of business you run. The Committee for a Responsible Federal Budget has a nice summary of the bill. Here are five proposals most likely to affect building material dealers and distributors.

The Mortgage Interest Deduction
Watch out, California. And in high-prices parts of Hawaii and Connecticut, beware. Today, homeowners there and elsewhere can deduct interest paid on mortgages of up to $1 million. For all new purchases, the tax reform package would limit deductibility to interest paid on the first $500,000. HousingWire quotes a Lending Tree analysis that found California has 13 of the top 15 markets nationwide for the percentage of residents who claim a mortgage interest deduction. The other two are Stamford-Norwalk, Conn., and Honolulu.

"Capping mortgage interest at $500,000 for new home purchases means that home buyers in expensive markets will effectively lose this housing tax benefit moving forward," Granger MacDonald, chairman of the National Association of Home Builders (NAHB), said in a statement.

Actually, only about 5% of mortgages that originated between 2012 and 2014 were for over $500,000, The Washington Post quoted an advocacy group as reporting. But the cut, combined with the fact many economists also believe that increasing the standard deduction will make lots of middle-class Americans less likely to use the mortgage interest deduction, leaves builders worried about the deduction's future. "Anything that's going to impact the sacred mortgage deduction is going to have a significant impact on home values here in Connecticut, and on excitement about owning a home," Scott Cooney, regional vice president for the Connecticut Association of Realtors, told The Washington Post.

Pass-Through Corporations
If you are an S Corporation or a limited liability company, the profits your business are passed through to the individuals who own it, and it's the individuals who pay taxes at whatever is the going rate. Roughly 95% of all businesses and 99% of businesses with revenues under $10 million are pass-through corporations.

Reports on how the bill would change the tax rates vary. According to The Washington Post, "70% of the income pass-through businesses earn will be taxed at the rate of the business owner’s individual tax rate (i.e. 25%, 35% or 39.6%) while the remaining 30% will be taxed at a new low rate of 25%. Another group summarized the measure as saying it calls for a 25% tax rate for passive owners of pass-through entities and 35% for passive owners.

All this may be good if you pay a higher personal rate, but not many people do.

"Nearly nine in 10 businesses that pass through their income already pay at the 25% rate or less," said John Arensmeyer, founder of Small Business Majority, an advocacy group. "Instead, this proposal would primarily help wealthy individuals rather than small businesses."

The National Federation of Independent Business announced it opposes the entire tax reform bill because it "leaves too many small businesses behind" and because the pass-through legislation does not help most small businesses. And the American Institute of Architects, while citing "serious concerns" about the legislation, said the bill excludes certain professional services from the lower 25% tax rate.

The Estate Tax
If you have run a successful small business, this one matters. According to the National Lumber & Building Material Dealers Association (NLBMDA), the bill doubles the estate tax exemption levels ($11.2 million for individuals, $22.4 million for couples) and indexes for inflation. It also repeals the estate tax and generation-skipping transfer tax starting in 2024, and cuts the gift tax to 35% on gifts over $10 million and indexes that amount for inflation.

Tax Brackets/Standard Deduction
There are seven brackets now, while the bill cuts these to four. Depending on how much you earn, it's possible you'll fall into a lower bracket. For instance, if you're a single filer with income over $92,000, you pay at the 28% tax rate. Under the House bill, you'd pay 25%. And if you don't itemize much, you could gain from the increase in standard deductions to $12,000 (from $6,350) for individuals and $24,000 (from $12,700) for couples.

The NAHB estimates that with such an increase in standard deductions, the number of returns using the mortgage interest deduction would drop to about 10 million from the current 34 million.

State, Local and Property Taxes
If you live in areas--particularly Northeastern states--that impose comparatively heavy state and local taxes, note that the reform bill will cap deductibility of state and local property to the first $10,000 of that bill.