Hawaii homeowner guide

Main water shutoff

At the meter near the street or at the wall entry. Hawaii's combination of salt air, humidity, and occasional seismic activity (particularly on the Big Island) stresses plumbing. Know your shutoff and test it annually.

HVAC and dehumidification

Hawaii's 70-90% relative humidity year-round means a properly functioning AC/dehumidification system is essential for indoor air quality. Without air conditioning and dehumidification, mold develops within days on any damp surface. Know your HVAC system's location, filter replacement schedule, and service provider.

Lava zone designation (Big Island only)

The Big Island has 9 lava zones. Zone 1 (active lava flows) has no current residential infrastructure. Zone 2 (Puna, lower East Rift) is where most lava-related home losses occur, including 2018 where Leilani Estates lost 700+ homes. Know your lava zone. It affects insurability, risk, and emergency planning.

Salt air corrosion monitoring

Hawaii's salt air attacks metal surfaces, fasteners, HVAC coils, electrical connections, and appliances. Monthly: inspect visible metal components for rust. Annually: have HVAC coils inspected for salt air corrosion (coastal Hawaii coils corrode in 3-5 years without treatment). Rinse exterior metal surfaces with fresh water regularly.

Mold monitoring

Hawaii's humidity means mold can develop on interior surfaces within days of any moisture intrusion. Check under sinks, in closets, on grout lines, and near any exterior wall penetrations monthly. A musty smell means immediate investigation.

Hurricane preparation in Hawaii

Hawaii hurricanes are uncommon but catastrophic when they occur. Iniki (1992) destroyed 1,400 homes on Kauai. Know your evacuation zone (Hawaii State Civil Defense publishes zone maps by island and county). Stock 7-14 days of supplies; post-hurricane supply chains to Hawaii are disrupted for weeks. Know the nearest shelter location.

Roof and hurricane strap inspection

Hawaii homes built before 1992 (pre-Iniki code upgrades) may lack hurricane straps. A licensed contractor can add hurricane connectors in the attic. Inspect the roof before hurricane season; lift-resistant roofing is critical in a tropical cyclone.

Flood and landslide risk management

Hawaii's wet season brings intense rainfall that causes flash flooding, stream overflow, and landslides. The North Shore of Oahu, Hana coast of Maui, and East side of the Big Island receive 100-400 inches of rain per year. Know your flood zone, maintain proper drainage around the foundation, and know your evacuation route from stream valleys.

Mold prevention during heavy rain season

Run AC continuously during wet season even when temperatures are comfortable; the AC system dehumidifies while cooling. Do not turn off AC when leaving for extended periods (not even 'to save electricity'); a Hawaii home without AC in wet season develops mold in days.

Annual salt air protection routine

Annually: rinse and treat all exterior metal with corrosion inhibitor (Corrosion X or equivalent for coastal Hawaii). Have HVAC coils inspected and treated. Check all metal fasteners in decks, railings, and roofing for corrosion. Replace corroded fasteners before they fail structurally.

Marine-grade specifications for all exterior components

In Hawaii's coastal environment (essentially the entire state), use only marine-grade stainless steel (316 grade) or galvanized fasteners, fittings, and hardware. Standard steel corrodes within 1-3 years. Budget for HVAC coil replacement every 5-8 years in salt-air-exposed locations.

Impact windows or storm shutters

Impact-resistant windows or storm shutters are essential for Hawaii hurricane preparedness. Standard single-pane windows fail in hurricane-force winds. Post-Iniki code requires impact-resistant glazing in new construction; pre-1992 homes should be upgraded.

Tsunami evacuation zones: know yours now

Hawaii has detailed tsunami evacuation zone maps (available at hawaiiema.gov). Every coastal county has multiple zones (A = highest risk). Know your zone, the evacuation route, and the location of the nearest shelter on high ground. Hawaii has experienced local tsunamis (from Hawaii earthquakes, within minutes) and distant tsunamis (from Alaska, Japan, and Chile, with hours of warning). Local tsunamis allow no time to wait for official warnings. If you feel sustained shaking near the coast, move to high ground immediately.

Vog and air quality monitoring

Volcanic fog (vog) from ongoing eruptions at Kilauea affects air quality across the Big Island and can reach Maui and Oahu. Monitor USGS Hawaiian Volcano Observatory air quality advisories. People with respiratory conditions should have N95 masks and know their triggers. Vog is particularly intense during trade wind reversals.

Lava flow preparedness

Lower Puna residents (Zone 2) should have a go-bag ready year-round. Lava flows don't always give weeks of warning; 2018 Leilani Estates residents had days to weeks before some areas were cut off. Keep essential documents, medications, and irreplaceable items easily transportable.

If you did not evacuate: shelter in place

Interior room, lowest floor above surge level, away from windows. Hurricane-force winds in Hawaii can exceed 150 mph. Do not go outside during the storm. Wait for the official all-clear from Hawaii Emergency Management Agency.

Local tsunami: feel shaking = go to high ground now

A local tsunami from a Hawaii earthquake gives 5-20 minutes before wave arrival. Do not wait for a siren or official warning. If you feel sustained shaking near the coast, move to high ground immediately on foot if roads are blocked. Distant tsunami (from Alaska or Pacific): you have hours; follow Hawaii Emergency Management Agency instructions.

Shut off and drain

Main water off at meter. Open all faucets. Hawaii plumber availability after major events (hurricanes, major earthquakes): wait times can be 48-96 hours as the entire state is affected simultaneously.

Flash flood and coastal flooding response

Hawaii homes rarely have basements. Flooding occurs at grade from flash floods, tsunami surge, and coastal inundation. Do not enter flooded areas with submerged electrical equipment. Call Hawaiian Electric (1-808-548-7311), MECO (1-808-871-8461), or HELCO (1-808-969-6999) to disconnect at the meter. Move to high ground.

Post-hurricane outages in Hawaii

Post-Iniki outages lasted weeks for some Kauai communities. Hawaiian Electric: 1-808-548-7311. MECO (Maui): 1-808-871-8461. HELCO (Big Island): 1-808-969-6999. KIUC (Kauai): 1-808-246-4300. Generator outside only, 20+ feet from windows. Hawaii heat and humidity make extended outages uncomfortable but less immediately dangerous than cold-climate outages.

Evacuate and call from outside

Rotten egg smell: everyone out. Leave door open. Call 911. Hawaii Gas: 1-808-526-0066. Propane: call your supplier. Do not re-enter until cleared.

Two exits, meet outside, never re-enter

Two ways out of every room. Specific outdoor meeting place. Crawl under smoke. Call 911. Never go back inside. Hawaii's humidity means interior fires can smolder for extended periods, but can flashover quickly when oxygen is introduced (as when a door is opened). Crawl low and move fast.