What to do after buying a house

Published July 21, 2026.

The highest-value first moves after buying a house are simple and mostly free. Change or rekey the exterior locks, find the main water shutoff, the gas shutoff, and the breaker panel, test every smoke and carbon monoxide alarm, set the water heater to about 120 F, make a home inventory for your insurance, and start a light maintenance routine. Do those in roughly that order and you have covered the things that protect your safety, your home, and your money. Everything else can wait. Our free new homeowner checklist turns this into a list you can check off and it saves your progress.

In the first week

Change or rekey every exterior lock. You have no idea how many copies of the old keys the previous owner handed to friends, family, babysitters, or contractors over the years, so This Old House recommends changing or rekeying the locks within your first week, ideally before you move belongings in. Rekeying is usually cheaper than replacing; new hardware makes sense if the locks are worn.

Find your shutoffs and the breaker panel. Locate the main water shutoff valve, which Bob Vila notes is usually where the water line enters the home, often in a basement, crawl space, or garage near the water heater. Find the gas shutoff and the electrical panel too. The panel is typically a gray metal box in a utility room, garage, or basement. Do this now, while it is calm, not during a burst pipe at midnight.

Test every smoke and carbon monoxide alarm. Press the test button on each one. NFPA recommends testing smoke alarms monthly, and they should be in every bedroom, outside each sleeping area, and on every level of the home including the basement. If an alarm does not sound, change the battery, and if the unit is over 10 years old, replace it. This matters more than it sounds: NFPA says the risk of dying in a home fire is roughly halved in homes with working smoke alarms. Give carbon monoxide alarms the same monthly test.

Home security, alarms, and gas are safety systems. When anything looks wrong or outdated, confirm with a licensed pro and your local codes rather than guessing.

In the first month

Set the water heater to about 120 F. The U.S. Department of Energy recommends around 120 F for most households, and many tanks arrive set higher. Turning it down is a rare win that improves safety and saves money at once. This Old House notes water at 140 F can cause third-degree burns in about five seconds, and that every 10 F reduction trims roughly 3 to 5 percent off your water heating costs. Check your model’s manual before adjusting the thermostat.

Change the HVAC filter and note the size. A dirty filter makes the system work harder and can lead to early failure, so Energy Star recommends inspecting, cleaning, or changing filters once a month, and at a minimum every three months. Write down the filter size while you are at it so reorders are painless. If you want the details, we have a full guide on how often to change your HVAC filter.

Make a home inventory for insurance. This is the step almost everyone skips and regrets after a loss. The Insurance Information Institute says a home inventory helps settle a claim faster, verify losses for your taxes, and confirm you are carrying the right amount of coverage. The quick version is to walk through each room with your phone, photograph or video the contents, and note make, model, and rough purchase price for the bigger items. Keep receipts for valuables, and store a backup somewhere off-site or in the cloud so it survives the same event you would be claiming for.

In the first few months

Meet your house. Label the breaker panel circuit by circuit, find the water heater’s age and model, and locate the HVAC unit, the sump pump if you have one, and any well or septic components. Knowing what you own makes every future repair and every service call shorter.

Start a maintenance routine. The point of a first year is to turn one-time setup into a rhythm you can keep. Our home maintenance tracker lists the recurring jobs with sensible intervals so nothing quietly falls off. Pair that with the filter and alarm schedules above and most of your seasonal work is already planned.

Get to know the seasonal risks for your climate. A house in a freeze zone needs its hose bibs drained before winter; a hot, humid one leans harder on the AC and dehumidification. Walk the exterior once so you know where water drains, where the roof is aging, and where the grading sends runoff.

Ongoing and seasonal

A few habits carry most of the load year after year:

Monthly: press the test button on every smoke and carbon monoxide alarm, and check the HVAC filter, per NFPA and Energy Star.
Every 3 months: change the HVAC filter at the latest, sooner if it looks dirty or you have pets, following Energy Star.
Seasonally: clean gutters, check exterior caulk and weatherstripping, and prep for your region’s hardest season.
Once a year: update your home inventory after big purchases and review your coverage, as the Insurance Information Institute suggests.
On a 10-year clock: replace smoke alarms 10 years after the manufacture date on the back, even if they still beep, per NFPA.

None of this is urgent on any single day, which is exactly why it slips. A checklist you can tick off and a tracker that remembers the intervals do the remembering for you. Start with the free new homeowner checklist to lock in the first-week and first-month items, then let the home maintenance tracker carry the seasonal work.

Sources

Insurance Information Institute · How to create a home inventory. iii.org/article/how-create-home-inventory
NFPA · Smoke alarms (safety information and tip sheet). nfpa.org/education-and-research/home-fire-safety/smoke-alarms
ENERGY STAR · HVAC Maintenance Checklist. energystar.gov/saveathome/heating-cooling/maintenance-checklist
This Old House · How to Adjust Water Heater Temperature. thisoldhouse.com/heating-cooling/how-to-adjust-water-heater-temperature
This Old House · A Step by Step Guide to Changing Locks on a New Home. thisoldhouse.com/home-safety/open-house-changing-locks-on-a-new-home
Bob Vila · How to Turn Off Water to Your House. bobvila.com/articles/turn-off-water

New homeowner checklist →

Frequently asked questions

What should you do first after buying a house?

Handle the safety and access basics first. Change or rekey every exterior lock, since you have no idea how many copies of the old keys are out there, per This Old House. Then find the main water shutoff, the gas shutoff, and the breaker panel so you can act fast in an emergency. Test every smoke and carbon monoxide alarm the day you move in. The rest, like a home inventory and a maintenance routine, can follow in the first few weeks.

What temperature should I set a new water heater to?

The U.S. Department of Energy recommends about 120 F for most homes, and many tanks ship set higher. This Old House notes water at 140 F can cause third-degree burns in about five seconds, and that every 10 F you drop saves roughly 3 to 5 percent on water heating. Confirm the setting with your model's manual.

How often should I test smoke and carbon monoxide alarms?

Test them once a month by pressing the test button, per NFPA. Replace smoke alarms 10 years after the manufacture date printed on the back, even if they still beep. NFPA also says the risk of dying in a home fire is cut roughly in half in homes with working smoke alarms. You want alarms in every bedroom, outside each sleeping area, and on every level including the basement.