Homeowner Tax Basics: Deductions, Credits, and What to Do Before the Year Ends

Taxes are the part of homeownership nobody circles on the calendar, but a little knowledge goes a long way, and September is exactly the right time for it. This is the season to make the small decisions that show up on the return you will file next spring: what to track, which receipts to keep, and which projects to finish by December 31. I am a realtor, not a tax professional, so think of this as the friendly primer you bring to your preparer, not advice in itself. The goal is that you ask sharper questions and never discover a missed deduction in April.

I have worked in real estate since 1988, and across all those closings I have noticed the same pattern: the homeowners who feel calm at tax time are not the ones with the fanciest accountants. They are the ones who kept a folder of receipts, knew their own numbers, and asked their questions before the year ended. Fall is a gift for exactly that kind of homework, because there is still time to act before January 1. So let me walk you through the homeowner tax basics that actually matter, with a few extra notes for seniors and families in transition.

Start With the Question: Standard Deduction or Itemizing?

Before any homeowner deduction can help you, ask whether you will itemize at all. For the 2025 tax year the standard deduction was generous: $31,500 for married couples filing jointly and $15,750 for single filers, and the numbers edge upward most years. If your mortgage interest, property taxes, and charitable gifts do not add up to more than the standard deduction, then itemizing does not change your tax bill, and that is completely fine. It is simple math, not a mistake.

The way to find out takes about ten minutes. Pull your mortgage interest statement, also called Form 1098, add your property tax payments, and gather what you gave to charity. Compare the total to the standard deduction. If the itemized number comes out ahead, that is when the homeowner deductions actually start working for you. If it does not, you can stop worrying about them entirely. Your preparer can run this comparison in seconds, and it is a wonderful question to ask at your next visit. One more thing to know: the limit on deducting state and local taxes, which includes property taxes, was raised substantially for recent tax years, though it phases down for very high earners, so if your planning involves a big tax bill, this is a topic to run by a professional rather than guess.

Mortgage Interest: Worth Knowing Even When It Does Not Apply

The interest you pay on the loan you used to buy your home is generally deductible on up to $750,000 of mortgage debt for loans taken out after December 15, 2017. Because Southern California prices run high, many owners in the San Gabriel Valley carry loans near or above that line, so it is worth knowing where yours falls. Your lender sends the figure on Form 1098 every January without you having to ask.

The surprise most people miss is the home equity loan rule. Interest on a home equity loan or line of credit is deductible only when the money went to buy, build, or substantially improve the home. If you borrowed against the house to pay off credit cards or to take a vacation, that interest is generally not deductible. If you tapped your home equity this year, pull out the statement and remind yourself what the money paid for. And if you used it for improvements, ask your preparer, because that is exactly the kind of thing that belongs on the return.

Keep a Receipt Folder for Improvements: It Pays Twice

Here is the single most practical habit I can hand you: keep a folder, or a simple note on your phone, listing every significant home improvement with its receipt. It pays twice. First, some improvements earn energy credits in the year you make them, which I will get to in a moment. Second, improvements raise your cost basis, the number used to figure taxable gain when you eventually sell.

A quick example to make it concrete: imagine a home purchased for $500,000 that later sells for $700,000. Without any recorded improvements, the gain looks like $200,000. But if you can document $60,000 in qualifying improvements over the years, the gain drops to $140,000, because the improvements raised the cost basis. A new roof, a new water heater, a kitchen or bathroom remodel, an addition, new wiring, and similar substantial work all count. Simple repairs and routine maintenance generally do not. Keep the receipt, and if it helps, a photo, dated and filed once a year. I have watched sellers scramble for paperwork they knew existed somewhere, and honestly, half an hour a year avoids all of it.

Energy Upgrades: The Credit With a December Deadline

A handful of home energy projects still carry generous tax credits, and the one that matters here is that the credit belongs to the year the qualifying item is installed, what the tax folks call placed in service. Qualifying windows, doors, insulation, and heat pumps can qualify for a credit of 30% of the cost, up to about $3,200 combined in a single year, with separate limits for different categories of equipment. What that means for you: a heat pump or qualifying window project finished by December 31 can land on next spring's return, while the same work scheduled for January lands a full year later. If an energy project is on your list, that timing question alone is worth a conversation with a tax professional before you sign.

Bigger systems like solar panels have had generous credits in recent years, though the rules have shifted recently and vary by year, so always confirm what applies for the year you are purchasing. In every case, hang on to the receipts and the manufacturer's efficiency paperwork. The credit is only as good as the documentation that comes with the equipment.

Selling: The Two-of-Five Rule That Spares Most Homeowners

When the day eventually comes to sell, there is beautiful news hiding in the tax code. If you have owned and lived in a home as your primary residence for at least two of the five years before the sale, you can generally exclude up to $250,000 of gain, or $500,000 for married couples filing jointly. For many primary-home sellers, that means the gain from the sale of their own home owes no federal tax at all. My advice: have the conversation with your tax preparer before you list, not after you close, because timing rules and California's own treatment of gains, which are separate, are worth understanding while you can still plan around them.

This is also the moment the receipt folder pays off, because documented improvements lower your taxable gain the same way they raised your cost basis. And if a large gain, a second home, or rental years are part of your story, the rules get more detailed, which is precisely the situation where talking to a professional before you list saves money.

For Seniors in California: Three Quiet Helps Worth Knowing

If you are 55 or older, or helping a parent who is, California has three benefits that do not make headlines but can make a real difference on property taxes, and September is a fine month to learn about them.

The homeowners' exemption. Any owner who lives in their primary home can have $7,000 taken off the assessed value it is taxed on, which saves roughly $70 a year. It is claimed once with your county assessor, the paperwork is free, and there is a filing deadline early in the year. If you just bought, or just moved into a home you own, it is a short call that can quietly pay you back for years.

Proposition 19 for those 55 and over. When you sell one home and buy another in California, Proposition 19 lets you carry your old property tax base to the new home, anywhere in the state, up to three times in a lifetime. The new home has to be bought or newly built within two years before or after selling the old one, and the claim goes to the assessor's office in your new area. If the replacement costs the same or less, the old base value generally transfers intact, which can keep a future tax bill far lower than an outsider would expect. For seniors thinking about downsizing, this can change the entire math of the move, and it is worth lining up long before the garage sale.

Property tax postponement for 62 and over. The state runs a program that lets qualified seniors defer their current-year property taxes as a low-cost loan, repaid when the home is sold or ownership changes hands. It has income and equity limits: in recent seasons, around $55,000 to $57,000 in total household income and at least 40% equity in the home. Applications typically open in the spring and can run into the fall. If that fits your situation, a brief call to the State Controller's office or your county assessor is the fastest way to get this season's exact numbers.

A Short Year-End List You Can Finish in an Hour

Here is the whole article in a few boxes you can knock out before the holidays:

• Pull your mortgage interest statement and property tax totals, and let your preparer compare them against the standard deduction once. It takes them minutes.
• Start the folder habit: a simple slot in a drawer, or a note in your phone, for this year's major improvement receipts.
• Decide on any energy project before December 31 so the timing works for you instead of against you.
• Bring up any 55-plus move as early as you are thinking about it, because Proposition 19 and the postponement program run on deadlines you want to be ahead of.

You do not need to do all of it today; you only need to do it before the year ends rather than after.

None of this is advice, and none of it replaces a conversation with the professional who prepares your return. It is the map, drawn by someone who has watched three decades of homeowners walk this path, and the ones who take the hour in the fall are the ones who breathe easy in April. And when the move itself comes up, whether a sale, a downsizing, a family transition, or settling an inheritance, I am the person to call for the part of the journey I do know backwards and forwards. Let us have a conversation. I am here to help.