Rain In Hawaiʻi Can Ruin Your Home (If You Ignore This)

Hawaii Property Market
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1 Video View·Dec 28, 2025
Rain in Hawaiʻi Can RUIN Your Home (If You Ignore This)
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Rain changes EVERYTHING in Hawaiʻi real estate — and most buyers don’t think about it until it’s too late.
It’s a rainy day in Hawaiʻi, and today we’re breaking down how rain affects your life, your home, and your buying decisions across the islands. From mountain runoff and flood zones to foundation types, mold, traffic, and insurance — this is the stuff no one explains until you’re already in escrow.
It's a rainy day in Hawaii. This is Hawaii's number one real estate channel.
We're going to talk about how the rain affects you as a homeowner,
affects your decisions on where to buy and what rain means for your life here in Hawaii.
All right, before we get really going, go to coreteamhawaii.com for all your real estate
needs. And if you watch this channel, enjoy it. Would you do me a favor? Would you like
and subscribe? I don't always do it, but could you do it for me? Like and subscribe if you get
value out of the channel. So today we're going to talk about rain. I have my surf shorts and
if it started storming, I was going to do a segment like that. But in lieu of that,
let's just get to actual real estate business. One of the first things I thought of was runoff
down mountains. We're not in a place like Florida at sea level. And there are concerns there,
but there are mountains, right? So there's not, you're living on the edge of this mountain and
all of that water is going to come down, right? This could be important. Even if you live in a
flatter part, like in core ridge, the new construction in Waipio, or maybe even parts
is just kind of here and you're here and you got to pay attention. Talk to your home inspector,
maybe hire a contractor for that home inspection too. And say, Hey, do we need like a French drain
or like a pump or something? Because my neighbor sits higher than me. These are things you have to
worry about. So on the side of that cliff, all that water has to go somewhere. That doesn't
mean don't live on the cliff, but a couple of things I want to think about, what kind of land
am I on? Am I on soil or am I on lava rock? We'll talk more about that later in the video.
And how is my house defended from this, right? Like, do I have a retaining wall? If I do have
a retaining wall, like this concrete wall here, or as we go down, wait on there, like some of
these lava rock walls, how's the condition of it? Has it suffered a bunch of rain, extra weight and
pressure pushing against the wall? Is it starting to fail? Is my house properly defended from the
elements if I live on the side of a cliff? For me, if it's less soil and more rock, I could still be
okay with it. Side side note, when there's rain and there's mountains, there's rocks, there's
landslides, there's sometimes rock slides. There was like someone who lived in a valley somewhere
in the last several years, and this boulder came flying through their house, would have killed
anyone in its way, happened to miss all the humans and the boulder just right through the house.
That's another thing to think about. That's more along the lines of like, you live in Hawaii,
do the volcanoes explode or, you know, stuff like that. Not a real issue most times, but maybe
something to think about if that would be an issue for you. So another thing to think about, this
really goes for anywhere, not just Hawaii, are vicious dogs. No, but what I was going to do, I
was going to point to the concrete there and how it's diverting away from the house. I've seen
homes either sold or how people buy homes where that may be an issue. Say this is the house,
you don't want sidewalks and outer perimeters that are going towards your house and bringing
water to the house, right? You want it to flow away from the house. Although I don't know the
exactly. I've been told by someone in the past that needs to be at least three degrees. So our
home inspectors could check me on that, but definitely want the water flowing away. All right,
guys. So another thing, flood zones, pretend this is a river of sorts. Cause if you look on the map,
you go deep into one of that. I've never been back there, but there's a stream or river of
sorts that comes from the mountains, flows towards the ocean, right? When most people
think of flood zones, you're thinking near the ocean, almost all buyers who are like, well,
I don't know. Is it a flood zone? They sometimes are conflating tsunami zone with flood zone.
Cause some places can be not a flood zone, but in the tsunami zone, but more often than not,
people are thinking of shoreline properties when they're thinking flood zone. But you also have to
think about these rivers and these mountains and this mountain rain runoff. A great example of that
or a horrible example of that is in Haleiwa. In Haleiwa, it's this surf town that's near the beach,
but not near the ocean. The Dole pineapple farm, they have a dam and they dam water. And if they
release the dams after really heavy rains, because the dams are going to break and Haleiwa can flood.
There have been houses floating in Haleiwa. Those homes are a mile or two from the ocean. This home
behind Kenji actually with the cool guava smoke sticker. We've eaten guava smoked on the channel
in the early days. So shout out to guava smoke. Actually looked some of these homes up before we
came and they're in the AE flood zone. The bad flood zones, the ones that you want to look out
for because either you just don't want to live in a flood zone and or you don't want to deal with the
difficulty in getting insurance and or the increased insurance cost because you live in an AE
or VE or AEF or VEF flood zone. These homes are AE or at least one of them that I looked up was AE.
So probably be most of them because imagine if this thing fills up, your home floods. Flood zones
happen far away from the ocean, even towards the mountains. And that's something you need to look
out for. So one thing you might think about when you're thinking about rain, rain make earth wet
house built on earth, earth become unstable foundation problem. Now I'm not a foundation
expert, but I did a little research and of course through many escrows, you know, we had a client
buy one house. I've told her, I told the story on the channel, but I wrote them a email documenting.
We support you pulling out. Don't have to buy this house. They said, thank you. We want to buy it.
This house had a seven inch difference across like 30 feet. You walked in some door frames are
straight ceiling crooked. It made you dizzy. When you walk, it's like walking in a fun house. If you
came to the side, but now they fixed it all and it's all cherry. And it's one of the most beautiful
views on the island. Foundation problems happen in Hawaii, just like they happen anywhere else.
So there's really three types of substrate or land that homes are typically built on in Hawaii,
rock, soil, and coral. So in Eva beach, I've heard that it's hard to put in swimming pools
and it can be hard to do certain things in the land because as soon as they go through the top
soil, you're in coral reef builders are building on primarily a coral foundation, depending on
where you are and have a beach. So don't watch this video and say, Hey, Derek, the bald guy from
YouTube said that if I buy an ever beach, I'm on solid foundation. That's not what I'm saying.
When I say that's the place where I've heard of people building on the type of land referred to
as like coral substrate, then you can build on lava rock in the diamond head area. There are a bunch
of homes on all kinds of cliff sides and hillsides, literally like right outside of the
house. You just dig with a spade or like a small shovel and you hit black rock. Those homes are
pretty solid. Now might they have rain runoff in some of those problems? Sure. But I don't think
they're going to slip away and erode and have those types of foundation problems. Typically,
then there's soil and part of Manoa you're building on more rock and it's more solid.
And in the back of Manoa in the woodland area, there's a little bit more dirt and there's
erosion. Like in Kailua, for example, there's many parts of Kailua. We've done multiple videos
on Kailua and show like the 10 different pockets of Kailua and in the Kalaheo hillside area. We've
continually seen listings there saying, Hey, you know, foundation issues, et cetera, or
kind of more in the disclosure statement, they disclose that, Hey, every 10 years or so
we're reshoring up our foundation. And so when you have a lot of rain and you have
water washing it away, obviously you can get erosion. So let's talk about the foundation
types. So there's slab on grade and Poston pier. Those are the two main ones you'll see in Hawaii.
And so like this house, for example, they put concrete down flat, put the house on top.
We all have an idea of what that's like, right on the mainland. I say on the mainland broadly,
like the whole 48 States are the same, but in my experience, I feel like there's a lot of slab
on grade, a lot of pour the concrete, put the house on top, but then there's Poston pier.
My parents in Tennessee, their house was built Poston pier in Tennessee. They also have
foundation problems with their house. There's a part in the back bedroom where it's going like
this on the wall. So there's a difference in drywall tape, sort of D lambing and seeing a
line across the wall. Most of the home inspectors and contractors show you that it's not foundation,
but by a doorframe, you have this zigzag etch-a-sketch thing going probably foundation
problems. And my parents had that in Tennessee. There's a Poston pier house over here. We'll show
you can crawl under it. You could put your surfboards under it. Your plumbing could go
under. There's a, there's a void space under the house that is above the earth because the house,
every so many feet, there's a pier Poston pier. There's a piece of wood going down in most cases,
or maybe it's buried into the ground in this concrete. Again, not a contractor foundation
expert, but that's not on one solid piece of concrete. I don't know that a contractor,
especially in Hawaii would say one is better than the other. I think you use the right type
of foundation for the right situation. Now, if you're on a hillside, like look at this road,
it may be that you start on concrete and then you have to go Poston pier because the land goes down,
right? You're like, you got to put something to support this stuff. That's hanging over the cliff,
like Tony Stark's house, right? I think even Tony Stark's house is probably Poston pier. We'll have
to go watch Ironman, but Poston pier foundation may be a little more vulnerable to erosion,
but also it's easier to fix. If the Poston pier is not touching, whatever guys come in and they
add soil and rocks and they'll do whatever they do and shore it back up. Whereas if it rains a ton
and you're on a concrete slab and it was, you know, 40 days and 40 nights and the land is wet
and you start getting some cracking and something like that. Now maybe you've got to bust through
your floor and you've got to lift up the floor and find the cracking. Again, I'm not a foundation
person. I'm just speaking from limited experience and some of the issues we've seen in escrow. Just
to summarize that last part, two types of foundation that are popular in Hawaii, slab on
or pouring out a big piece of concrete or Poston pier foundation. And then depending on the
topography on the soil type, the area of the Island, and even on the budget, you might see
either one of those two types of foundation. And then the three types of substrate or land that
people are typically building on a rock coral, and then looser soil. One thing you have to deal with
when it rains in Hawaii is bad traffic. We already don't have the best traffic, but when it rains,
we get flooding. Why do water mains break when there's rain? I don't really understand that,
but sometimes there's water main breaks. There's actually a part on the freeway, two or three lanes
of the freeway will flood out. I actually saw them this morning clearing that area out. If your
commute is an hour, you can plan on it being probably an hour and a half plus if it's a bad
rainy day. So not unique to Hawaii, you need to make sure that your roof integrity is intact and
good when it's going to be heavily raining. So you probably want to try and take care of that in the
summer. Don't wait for the first rain because after all, we don't have real seasons, but the
winter is more of a rainy season in terms of rain versus dryness. And there's several types of roofs
in Hawaii. So that kind of roof, you probably don't see it as much on the mainland, but it's this
instead of shingles, you know, place going down the steep slope, there's less of a slope. Actually,
I don't know the name of it, but they roll out these long things of asphalt type roof. You can
what they call a cool coat and they end up with just this not as steep white roof. There's also
shingle roof, which are probably still the most common, even in Hawaii. So if you know houses like
that one, you often see like these tile roofs and those can leak just like any other shingle roof.
One thing unique to Hawaii, and you don't see it as commonly here, big island, I would see it a lot.
Sometimes in like Waipahu, a tin roof. So it's a, it's a type of metal roof, but it's the one you
would think of probably if you're like on the mainland or if you live in Hawaii and you never
had a tin roof and you hear the rain just probably not the best defense against the elements, but
a less expensive way to get a roof on your house. Another thing to think about is solar and
electricity costs. When there's less sun, obviously there's less production of energy from the sun.
And so on rainy days, if you can't cut down on your AC usage, cause it's cooler, basically less
sun, less power, more power bill, less solar energy generated. Total side note, we had a client
reach out. I spoke to him two days ago. His electric bill was a thousand dollars. He's like, I bought
this house. It had 20 something panels. What's going on? Sent it to my solar guy. He said, yeah,
well, those panels are from 2013. Back then one panel produced half the kilowattage as the modern
panel. So 24 panels then is like 12 panels now, plus they're old. And so they're even less
efficient. So you have like 10 panels worth of usage on your roof. So that's something to think
about too, when you're buying there's 20 panels, there's 40 panels. Is there a battery? Is there
not? Is a net metering? How effective will the solar energy or the photovoltaic system actually
be? Don't just take panel number for face value and assume you're gonna have this little electric
bill. Because unfortunately this person who didn't buy with us has a thousand dollar electric
bill and it's maybe pushing them out of their house because their utility bills are so high.
I can tell it's a rainy area by rock walls and sidewalks. Most of that's just aesthetic nuisance.
Who cares? But in really rainy areas you get wood rot too. And so in Hawaii, sometimes it can be hard
to distinguish. Is that wood rot? Is that termite damage? Because both are common. So if I'm in
Ewa Beach and it's not around the gutters, like I don't have a failing gutter at an eve and
you know right there you'd expect maybe some wood rot because the rain just always hits that spot.
But if I'm in Ewa Beach and just some other part of wood, I can poke holes through it and whatnot.
That's probably termite damage. I don't know for sure but I could assume. If I'm in Kaneohe where
it's like this all the time, if I can kind of poke on the wood or like at the end of a piece of wood
where it's square there's kind of something missing, I have to ask myself is that termite damage?
Is it wood rot? I don't know. Something for the home inspector or contractor to look at
but something we want to bring up on a video about things being wet in Hawaii. So water obviously
causes corrosion. It can be bad for a home if the home isn't properly defended etc. Also mold growth.
Maybe if you're from the Pacific Northwest you think about this. In Hawaii we don't always think
about it depending on where you're from but when it's really wet outside like this, it's best to turn
on your AC and close the windows. That way you don't get all this moisture into your home but a
lot of homes in Hawaii don't even have AC. So your only option to get air in is to get all the moist
humid air in and potentially cause mold growth. You go into some homes in Hawaii and you see mold
growth in the closets and in these areas that get all this moisture. Don't get a lot of attention
you know because the board games and the books been stuffed in the back of the closet for a while.
We see that at times. Quick story on that. I just went to the mainland for a few days and I came
back. My bathroom doesn't have an exhaust fan yet. We mean to get it installed but we haven't. So we
just leave the window open kind of at all times. There's a little bit of you know in the bathtub
be a little bit of black going. So there's like just a little bit of black mold going. I was like
oh I hit it with the spray bleach when I get back. We came back days later it had grown. I was like
I was like how can it grow? Nobody was showering. Perfect example for this video. Enough moisture
and merilani is coming in through the window to feed that thing and give it enough moisture for
the mildew in the bathtub to grow even in the absence of people showering. So I thought that
was kind of crazy. If that can happen in the bathtub with the windows open with no one there
you have a home that you leave the windows open all the time or your previous owners left the
windows open all the time. Things you want to know to just make sure that you know closets and corners
and whatnot aren't moldy without you having that knowledge. I'm actually not super afraid of mold
because we can attack it and kill it with chemicals. You can cut out drywall. It's easy
to get rid of if you know it's there but that's one of the problems with a real moist season in
Hawaii. All right so we talked about traffic. We just want to mention a couple of other lifestyle
things. We don't really have a winter and so for like my wife who kind of longs to live part of the
year on the mainland and have that fall winter vibe and put on her boots and stuff. This rainy
season is a big rainy day like this is the closest thing we have to like you know getting a cup of
coffee and letting it warm your hands and my wife will turn on Harry Potter and make a whole winter
event out of it. The ranger is like the one time you get to do that. Also for hikers and swimmers
and cliff jumpers etc if you are that person you already know don't swim. Don't swim in our rivers
and in our ocean you know especially near an outlet right as it's raining or after it rains.
The ocean's beautiful and pristine and blue but there's just this brown murkiness that enters the water
and so we have this back is it a bacteria I guess called leptospirosis in Hawaii. You can actually
die from it. You want to make sure the water is clean when you go in it. Wait a few days. It can
be good to swim in the rivers and stuff you know days following the rain because you kind of have
like a flush of things. Pig feces and mongoose feces whatever all that comes into the river
right as it gets flushed out ends up in our rivers really dirty and then in our ocean so that's
something to think about too just for general like safety if you're going to live here in the rain.
You're surfing Ala Moana you know all of the places where the Ala Wai drains. The Ala Moana rock piles
all these waves. The Ala Wai canal is coming out right there. When I was young I used to be like I
just had this bias because I wanted to surf every day so I was like nah that's not the ocean is so
big and clean and it's salt and whatever but people can get sick sometimes and even you know
start to get like stomach flu symptoms after surfing right after a rainfall so something to
look out for. One thing people might not think about is home size. Say I'm gonna buy in Kona
on the big island and I'm a fisherman and I like to kayak and I basically I spend most of my time
out of my house. It's a fairly sunny place. Kona's got some weird microclimates but
you know maybe I can deal with a little less square footage but one of the reasons why real
estate in Alaska and in Minnesota whatever on average you need a bigger house is you have to
hunker down and make it through a winter. You know the rain gets irritating you know if you have 40
days straight of rain and you live in a 400 square foot place might get a little bit old. Look at the
climate you're buying in and assuming your budget has some flexibility that might be something to
consider. Something that you probably weren't thinking to hear is insurance. Make sure your
insurance is good to go before the rainy season. You don't want to wait until the water has caused
the brown spot on your roof and whatnot and you realize oh my insurance had expired because
Geico pulled out of Hawaii after the Maui fires and I didn't realize my policy didn't renew or
whatever the case may be. Now if you have a loan on your home it's unlikely that that's going to
happen because you're required to have insurance with the loan etc but just don't let your insurance
lap. That's a boring thing who wants to talk about insurance but you want to make sure your insurance
is good before the rainy season. It's something it's probably like an October checklist everyone
goes through before it starts raining a lot here in Hawaii in December, January, February. Speaking
of rainy days do not wait for a rainy day to go to courtinghawaii.com for all your real estate needs.
Like this channel, subscribe to this channel. Again I appreciate it if you did. I don't like
subscribe to everyone but if you find this valuable, find it entertaining, helpful, not only
like and subscribe but call us. One of the listing conversations that I had this week the guy ended
up with a different agent when he moved here and I was thinking about selling and I just have to
ask like did you know about us then and he said yeah you know I saw your videos but I just didn't
call you and I'm calling us. Call us on the buy. We'll help you on the sale. We'll bring this channel
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See you guys on the next one.
