Preparing a San Diego Vacation Home for Extended Vacancy: What Owners Should Check (2026)

What should you do before leaving a San Diego vacation home vacant for an extended period? Shut off the main water supply (or have a property manager flush fixtures weekly), set the HVAC to a maintenance temperature, secure all entry points against pests, verify the roof and exterior are watertight, clear gutters and downspouts, confirm the irrigation system is properly programmed or shut down, and arrange for periodic property checks during the absence.

Leaving a San Diego vacation home unoccupied for months at a time is normal. What isn't normal is the damage that can accumulate during that absence if the home isn't properly prepared. A small plumbing leak that would be caught in a day in an occupied home can run for three months in a vacant one, causing thousands of dollars in water damage and creating mold conditions that spread through the wall cavity before anyone opens the front door.

San Diego's climate makes some vacancy risks less severe than in cold-weather markets (no frozen pipes, no ice dam damage), but it creates others. Heat buildup in a closed home stresses finishes and adhesives. Dry conditions dry out plumbing seals faster. And the extreme heat events that have become more common in recent years can push interior temperatures in a closed, un-cooled home well above 100°F, which accelerates deterioration of everything from caulking to appliance seals.

This guide covers what to check and prepare before leaving your vacation home for an extended period, organized by system.

Plumbing: The Highest-Risk System During Vacancy

Water Shutoff Decision

The single most effective thing you can do to protect a vacant home from water damage is shut off the main water supply. No water pressure means no leaks. No leaks means no water damage, no mold, and no emergency plumber visit while you're 2,000 miles away.

The tradeoff: with the water off, toilets can't be flushed by a property manager during periodic checks, irrigation won't run from the domestic supply (if it's connected), and fire suppression systems (if present) won't function. If any of these are critical, an alternative is to keep the water on but have a property manager visit weekly to check for leaks and flush all fixtures. Weekly flushing keeps the p-traps full and prevents stagnant water from becoming a bacterial growth concern.

Water Heater

If the water is shut off, turn the water heater to its lowest setting or "vacation" mode. Running a water heater with no water flow wastes energy and can overheat the tank. If you're shutting off the water entirely, some homeowners turn off the water heater completely (electric: breaker off; gas: pilot off).

Irrigation System

If the irrigation system runs from the domestic water supply, shutting off the main water also shuts off the irrigation. You have two options: leave the water on and risk a plumbing leak (while maintaining the landscaping), or shut the water off and arrange for a yard maintenance service to water manually or from an alternative source.

If the irrigation has its own dedicated meter and supply (common on larger San Diego properties), you can shut off the domestic water while leaving the irrigation operational. This protects the interior plumbing while maintaining the landscaping.

HVAC: Keep It Running, Just Barely

Don't turn the HVAC completely off. A closed home in San Diego can reach 100°F to 120°F during summer heat events, and that heat accelerates deterioration of finishes, adhesives, electronics, and stored items. Extreme heat in a closed home also stresses the roof assembly from below, adding to the damage potential we've covered in our attic and radiant barrier inspection guide.

Set the thermostat to 85°F for cooling. This prevents extreme heat buildup without running the system constantly. The goal is to prevent temperature-related damage, not to keep the home comfortable for nobody.

Set the thermostat to 55°F for heating (relevant during San Diego's occasional cold snaps in December through February, especially in inland and mountain areas).

Check the HVAC filter before leaving. A dirty filter restricts airflow and makes the system work harder. Replace it before you leave so the system operates efficiently during your absence.

Clear the condensate drain. A clogged condensate drain can cause water to back up and overflow into the home. Flush the drain line with a cup of vinegar before leaving.

Roof and Exterior: Seal It Tight

Walk the exterior before you leave and check for any conditions that could let water or pests in during your absence.

Roof. Check for missing or damaged shingles, cracked flashing, and any debris on the roof surface. If you're leaving before the rainy season (November through March in San Diego), any roof deficiency that allows water entry will cause undetected damage for the entire duration of your absence.

Gutters and downspouts. Clean all gutters and verify downspouts are clear and routing water away from the foundation. Clogged gutters during a rain event overflow against the fascia and can drive water into the soffit, the attic, and behind the exterior walls.

Windows and doors. Verify all windows and doors close and lock securely. Check weatherstripping and caulking for gaps that could allow pest entry or water intrusion during wind-driven rain.

Exterior penetrations. Check all utility penetrations (electrical conduit, plumbing lines, HVAC lines, cable/internet) for gaps or missing sealant. These are common entry points for insects and rodents.

Pest Prevention

An unoccupied home is an attractive target for pests. Before leaving, take these steps.

Seal all exterior gaps. Any opening larger than 1/4 inch can admit mice. Any opening larger than 1/2 inch can admit rats. Check foundation vents (should have intact screens), eave closures, utility penetrations, and door sweeps.

Remove all food. Empty the refrigerator and pantry of perishables. Wipe down all surfaces. Take out all trash. Sealed dry goods can remain if they're in airtight containers.

Set pest prevention measures. Place bait stations or traps in the garage, attic access area, and under sinks. Consider a quarterly pest control service during your absence.

Check the attic and crawl space before leaving. Verify there's no existing pest activity. Address any evidence of rodents, ants, or wildlife before you leave, because a small problem in an unoccupied home becomes a large problem over several months.

Electrical System

Unplug non-essential electronics to protect against power surge damage and reduce phantom energy draw.

Leave the electrical panel on. The HVAC, the security system, the refrigerator (if you're keeping it running), and any smart home monitoring systems need power.

Test GFCI outlets. Press the test button on all GFCI outlets (kitchen, bathrooms, garage, exterior) and verify they trip and reset. A tripped GFCI that doesn't reset could indicate a wiring issue that should be addressed before you leave.

Check smoke and CO detectors. Replace batteries if they're older than 6 months. Test each detector. These are your only alert system for fire and CO during your absence (along with any connected smart detectors).

Drainage and Foundation

Check grading around the foundation. Verify the soil slopes away from the house on all sides. If grading has settled or eroded since your last visit, correct it before you leave. Rainfall on negatively graded soil will direct water toward the foundation for the entire rainy season without anyone there to notice the pooling.

Check irrigation head alignment. If the irrigation will run during your absence, verify no heads are spraying against the house. Overspray against the foundation during months of unattended operation can saturate the soil and create foundation moisture problems in San Diego's expansive clay.

Security and Monitoring

Set up a property check schedule. Ideally, someone should walk through the home every 1 to 2 weeks to check for leaks, pest evidence, HVAC operation, and any visible problems. A property manager, a trusted neighbor, or a house-sitting service can handle this.

Install water leak sensors. Battery-powered leak sensors placed under sinks, near the water heater, near the washing machine connections, and in the crawl space (if accessible) can alert you to leaks via smartphone notification. These cost $20 to $50 each and can prevent thousands in water damage.

Verify your homeowner's insurance covers extended vacancy. Most standard policies limit or exclude coverage when a home is unoccupied for 30 to 60+ consecutive days. Contact your insurer before leaving to confirm coverage, add a vacancy endorsement if needed, or switch to a vacant property policy.

The Pre-Vacancy Inspection Checklist

System	Before You Leave	During Vacancy (Property Manager)
Plumbing	Shut off main water or arrange weekly flushing. Set water heater to vacation mode.	Check for leaks weekly. Flush all fixtures.
HVAC	Replace filter. Clear condensate drain. Set thermostat to 85°F cooling / 55°F heating.	Verify system running monthly. Check for unusual sounds or odors.
Roof	Inspect for damage. Clean gutters and downspouts.	Visual check monthly, especially after storms.
Pest prevention	Seal gaps. Remove food. Set traps/bait stations.	Check traps monthly. Note any new evidence of activity.
Electrical	Unplug non-essentials. Test GFCIs. Replace detector batteries.	Verify panel on. Check for tripped breakers.
Drainage	Correct grading. Check irrigation alignment.	Monitor for pooling or erosion after rain.
Security	Set alarm. Install leak sensors. Confirm insurance coverage.	Weekly walkthrough. Collect mail. Maintain appearance.

How 360 Home Inspection Can Help Before and After Extended Vacancy

We offer pre-vacancy inspections that identify conditions that should be addressed before you leave and post-vacancy inspections when you return (or when a buyer is evaluating a property that's been vacant).

A pre-vacancy inspection gives you a documented baseline of the home's condition before the absence. When you return or when a buyer inspects the property, any changes from that baseline are attributable to the vacancy period, which simplifies insurance claims and repair prioritization.

For the full scope of our inspection, see our buyer's guide.

Schedule your inspection or call (858) 707-7066.

Frequently Asked Questions

Q: Should I shut off the water before leaving my vacation home vacant?

Yes, in most cases. Shutting off the main water supply eliminates the risk of plumbing leaks causing water damage during your absence. The tradeoff is that irrigation (if connected to the domestic supply) and toilets won't function. If you keep the water on, arrange for weekly property checks that include flushing all fixtures.

Q: How long can a house sit vacant before problems start?

Plumbing issues (p-trap evaporation, seal drying) can begin within 3 to 6 months. Pest intrusion can begin within weeks. HVAC degradation becomes a concern after 6 to 12 months of non-use. Undetected leaks can cause significant hidden damage within a single rainy season.

Q: What temperature should I set the thermostat to in a vacant San Diego home?

Set the cooling thermostat to 85°F to prevent extreme heat buildup without running the system constantly. For heating during winter months, set it to 55°F to prevent cold-snap damage to plumbing and finishes. Don't turn the HVAC completely off.

Q: Does homeowner's insurance cover a vacant vacation home?

Most standard policies limit or exclude coverage when a home is unoccupied for 30 to 60 consecutive days. Contact your insurer before the vacancy to confirm coverage, add a vacancy endorsement, or obtain a separate vacant property policy. The cost of the endorsement is minimal compared to the cost of an uninsured loss.

Q: How do I prevent mold in a vacant home?

Maintain HVAC operation (even at a minimal setting) to keep air circulating. Ensure the roof and exterior are watertight. Fix any known moisture issues before leaving. Have a property manager check for musty odors and visible moisture during periodic visits. In San Diego's climate, mold risk is highest in closed, un-ventilated spaces with undetected moisture sources.

Q: Should I have my vacation home inspected before leaving it vacant?

A pre-vacancy inspection identifies conditions that should be corrected before the absence: roof deficiencies, plumbing leaks, pest entry points, drainage problems, and HVAC issues. It also creates a documented baseline of the home's condition, which is valuable for insurance purposes and for comparison when you return.

Q: How often should someone check a vacant vacation home?

Every 1 to 2 weeks is ideal. The property check should include a walkthrough of every room (looking for leaks, odors, pest evidence), flushing all fixtures (if the water is on), verifying the HVAC is running, checking for tripped breakers, and a brief exterior walk to look for damage, drainage issues, or pest entry.

Q: What is the biggest risk to a vacant home in San Diego?

Undetected water intrusion (from roof leaks, plumbing failures, or irrigation overspray) is the biggest risk because it causes the most expensive damage (water damage repair, mold remediation) and is the hardest to detect without regular property checks. A small leak running for months in a vacant home can cause $5,000 to $20,000+ in damage.

Q: Can I leave appliances running in a vacant home?

The HVAC should remain on at a maintenance setting. The refrigerator can stay on if it contains items or if you want to keep it operational (empty it and set it to a moderate temperature). The water heater should be set to vacation mode or turned off. All other appliances should be unplugged to prevent phantom energy draw and surge damage.

Q: What pest prevention should I do before leaving a home vacant?

Seal all exterior gaps larger than 1/4 inch, remove all perishable food, wipe down surfaces, take out trash, place bait stations or traps in the garage, attic access, and under sinks, and check the attic and crawl space for existing pest activity. Consider a quarterly pest control service during the vacancy.

Final Thoughts

Leaving a vacation home vacant for months isn't neglect. It's a normal part of owning a second property. But the home doesn't stop needing attention just because you're not there.

Shut off the water. Set the thermostat. Seal the gaps. Clean the gutters. And arrange for someone to walk through every couple of weeks to catch the problems that develop in silence.

The cost of preparation is measured in hours and a few hundred dollars. The cost of coming back to a flooded crawl space, a mold-infested wall cavity, or a rodent-damaged attic is measured in thousands.

Maintenance recommendations and cost estimates in this article reflect San Diego conditions as of 2026. Property maintenance requirements, insurance coverage, and service costs vary by property, location, and provider. Consult your insurance provider and licensed professionals for guidance specific to your property.