What to Do in the First 30 Days After Buying a House

The keys are yours, the boxes are everywhere, and every system in the house is a stranger. The first 30 days are when you learn how your house works — and when you set up the records and routines that make the next ten years of ownership easy.

This checklist is ordered by urgency: safety and access first, then documentation, then the preventive tasks that set up your ongoing routine. Tick tasks off below as you go; each one links to how to do it.

Days 1–3: Safety and Access

Find the three shutoffs

Before you unpack a single box, locate and label these. In an emergency, seconds matter. Our emergency shutoffs guide covers every valve and switch to find, and which ones to leave to the utility.

• Main water shutoff. Usually near where the water line enters the house — a basement wall, utility room, crawlspace, or garage. Turn it until it stops to confirm it actually works (old valves seize; if it won't budge, have a plumber free it up now). Show every adult in the house where it is.
• Breaker box (electrical panel). Flip nothing yet — just verify the panel directory is accurate by testing a few circuits. A mislabeled panel is normal; you'll fix the labels in week two.
• Gas shutoff. If you have gas service, find the shutoff valve on the gas meter outside (it usually needs a wrench to turn) and the shutoffs on individual appliances. If you ever smell gas, leave the house without switching anything on or off, call 911 and the gas company once you're a safe distance away, and don't relight anything yourself.

Change the locks

You have no idea how many copies of your keys exist: previous owners, their relatives, contractors, dog walkers, neighbors. Replacing the exterior door locks (or having a locksmith re-key them) in the first few days is the single highest-value security move a new homeowner can make. Reset garage-door opener codes and smart-lock passcodes too. If you are replacing the deadbolts anyway, our smart lock guide explains which models come with a new cylinder and which keep the old one.

Check every smoke and CO alarm

Walk the house and confirm there's a working smoke alarm inside every bedroom, outside each sleeping area, and on every level (including the basement) — that's the NFPA placement recommendation. Then turn each unit around and read the manufacture date: smoke alarms must be replaced at least every 10 years, per the NFPA, and carbon-monoxide alarms typically expire after 5–10 years depending on the model (the replace-by date is printed on the unit). Test every alarm with the test button. If anything is missing, expired, or silent, replacing it is a day-one errand, not a someday task; our smoke and CO alarm guide covers which type to buy for each spot.

Days 4–10: Document Everything

Record appliance model and serial numbers

Open every appliance — furnace, water heater, fridge, washer, dryer, dishwasher, oven, AC unit — and photograph the model and serial number plate. Those numbers are the first thing a manual or a repair tech asks for when, say, the dishwasher won't drain or the oven won't heat. Save the photos to the cloud, not just your phone. The next time an appliance fails, the first question from any technician or parts desk will be "what's the model number?" — and you'll have it in seconds.

Note the HVAC filter size and buy spares

Pull the furnace or air-handler filter and write down its exact dimensions (printed on the frame, e.g. 16x25x1). ENERGY STAR advises checking the filter every month and changing it at a minimum every three months — and you can't follow that habit if you don't know the size. Buy a multi-pack in the right size now; a filter you own gets changed, a filter you have to shop for doesn't.

Start the home document binder

Get a simple binder or a clearly labeled cloud folder and start filling it:

• The home inspection report — every "near end of life" note becomes a savings line in your maintenance budget, and our inspection report decoder explains common findings in plain English. Handle the safety findings first, such as a garage door that doesn't reverse, a range without an anti-tip bracket, a loose or missing handrail, an outlet with reversed polarity, or a garage entry door that isn't fire-rated and self-closing.
• Appliance manuals (photograph the model plates as above; most manuals are available as PDFs from the manufacturer).
• Warranty paperwork: roof, windows, appliances, and builder warranties with expiration dates and claim phone numbers.
• The seller's disclosures and any permits for past work.
• A running log: every repair, service visit, and filter change gets a date and a note.

Fix the breaker panel labels

With a partner and 20 minutes, flip breakers one at a time and label every circuit accurately ("kitchen outlets," not "plugs"). Tape the directory inside the panel door. Accurate labels turn a 2 AM electrical problem from a guessing game into a one-minute fix.

Days 11–20: Verify the Big Systems

Set the water heater and check its age

Find the water heater's manufacture date on its label and calculate its age — a typical storage water heater lasts 10–15 years, so a 13-year-old unit means "start saving," not "panic." Confirm the thermostat is set to 120°F, the Department of Energy's recommendation for most households. Test the temperature-and-pressure relief valve by briefly lifting the lever — water should flow, then stop. That water is scalding hot, so first confirm the valve's discharge pipe runs down to a drain or a bucket and keep your hands clear; if there is no discharge pipe, skip the test and call a plumber. If the valve is old and hasn't been tested in years, have a plumber do this one: lifting a long-neglected lever can start a drip that won't stop. Look for rust, pooling water, or corrosion at the fittings.

Check the fridge and freezer temperatures

Set a cheap appliance thermometer in each compartment and check after a few hours: the FDA recommends the refrigerator at 40°F or below and the freezer at 0°F. Adjust the controls until both are solidly in range. While you're there, check whether the manual calls for cleaning the condenser coils; many newer models don't need it. If yours does, unplug the fridge first; our fridge guide walks through it.

Test every GFCI outlet

The National Electrical Code requires GFCI protection in bathrooms, kitchens, garages, outdoor receptacles, basements, crawl spaces, and laundry areas. Press "test" on each one (power should cut), then "reset". Any outlet that fails needs replacing — a like-for-like swap is a careful-DIY job (see our DIY guide), or have an electrician do it.

Inspect the dryer vent situation

Check what the dryer vents through: it should be a smooth metal duct running directly outside — not plastic, not crushed foil accordion tubing, and not venting into the attic or crawlspace. NFPA data shows roughly a third of dryer fires come from failure to clean, so note the vent's condition, clean it if it's due, and add annual vent cleaning to your calendar.

Test for radon

The EPA and the Surgeon General recommend testing every home below the third floor. The EPA also suggests a new test if the seller's result isn't recent, the house was renovated since, or the test was taken on a higher floor than the one you'll live on. A short-term kit on the lowest lived-in level runs as little as two days. Our radon test kit guide covers how to test and what the number means.

Days 21–30: Set Up the Routine

Walk the water

Learn where water can hurt you: check under every sink, around toilets, behind the washing machine, and at the water heater for any dampness. Find the shutoffs for the washing machine and each toilet (the small valves on the supply lines). Consider smart water-leak detectors — inexpensive devices that alert your phone when they sense water — near the water heater, washer, and under sinks if you travel.

Start the monthly habits

The entire maintenance routine rests on two monthly habits: check the HVAC filter and test the smoke alarms. Put both on a recurring calendar reminder right now. Everything else in a month-by-month maintenance calendar builds on this foundation.

Review insurance and warranties

Read your homeowner's insurance declarations page — not just the price. Confirm coverage amounts, the deductible, and exclusions (flood and earthquake are usually separate policies). Photograph every room for a home inventory and store it in the cloud. If the seller included a home warranty, read what it covers before you need it.

Learn the systems' history

Call the HVAC company that last serviced the system (the sticker is usually on the unit) and ask about its age and history. Do the same for the roof if there's warranty paperwork. Knowing "the furnace is 9 years old and was serviced last fall" is the difference between budgeting calmly and being blindsided.

Common First-Month Mistakes

• Skipping the locks. It feels like a later task. It isn't — rekey within days.
• Trusting the old smoke alarms. Alarms don't look expired — they just quietly stop protecting you after 10 years. Check the dates.
• Throwing away the inspection report. It's not a pass/fail document — it's a multi-year maintenance and budgeting plan. Keep it in the binder.
• Ignoring the first small leak. That faint dampness under the sink is cheapest to fix the day you find it. Water never fixes itself.

Bottom Line

Thirty days, four phases: secure the house (locks, alarms, shutoffs), document everything (model numbers, filter sizes, the binder), verify the big systems (water heater, fridge, GFCIs, dryer vent), and set up the monthly routine. Do this once, and the month-by-month calendar and annual budget that follow become easy instead of overwhelming. For the gear, our new homeowner shopping list puts it in the order you'll need it.

Sources

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