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Our first house was one a 1/2ac lot at the end (bottom -- this will become important later) of a cul-de-sac in a great semi-urban neighborhood in Cary, NC. We

Our first house was one a 1/2ac lot at the end (bottom -- this will become important later) of a cul-de-sac in a great semi-urban neighborhood in Cary, NC. We learned after repeated backyard flooding and near-incursion of storm water into our patio door that our street had been built on what had been the original stormwater collection pond for the larger neighborhood. The builder got permission from the city to move the pond to build our cul-de-sac, but that didn't stop our street from still being the lowest point in the neighborhood, where all surface water ran-off to, and our house was at the very lowest point. Long story short, we ended up installing a french drain on two sides of our house, putting a drain at the end of our driveway to redirect water [from just running down our driveway to our house], having the front wall foundation rebuilt and jacked up because the footer had nearly completely eroded (1970s house), and still needed to add two 24" square drain boxes in the back yard (with buried 4" PVC draining into the creek at the back of the property) to remediate all this. It was also a tree-filled lot and the drain boxes would almost immediately clog with leaves during heavy rains, so I spent a lot of time out there in ankle to knee deep water with a rake to keep the drains clear. This still wasn't enough! We got a so much surface run-off from our uphill neighbors that it looked like a sheet of rushing water across our backyard during heavy storms. We had a creek at the back of the property but were not allowed to mess with it because of Corps of Engineers easement regulations. At the end of the day, we finally solved our problems by getting an agreement from our neighbor to let us dig a surface water drain from the low point in their yard into the creek, and then we'd build a "temporary" (cf prior easement rules against permanent walls) berm along the property line to prevent surface water from coming into our yard at all. That "berm" was 76 bags of Qwikrete stacked three high and covered with grass clippings, yard waste & mulch. Technically we could have removed it if the city had inspected, but it was very much a cement wall. We have never since, and never will, build or purchase a house at the bottom of a hill.

kbenson 2y ago
One of the prior houses I lived at had so much flooding and water leakage problems from poor construction (prior additions that weren't strictly legal) that lead to carpet and padding having to be removed from concrete floored rooms and eventually mold problems, that when I bought a house a few years after we'd ran away from that disaster of a house we made absolutely sure to my at the high point of the (new) neighborhood so we weren't in the drainage path for anyone. It's particularly demoralizing to see the scope of the problem when it's all that water flooding your property and know there's nothing you can do in the short term, and even the long term is just trying different things and hoping they work, knowing that it will probably take a few tries.
- bradknowles 2y ago
  Flooding can come in many forms. Perhaps the balcony over your front door is not properly constructed and is not properly shedding rain, so one day during a torrential thunderstorm you suddenly have a flood coming in OVER your front door. Perhaps your water heater pan is not draining correctly, and one day you have a catastrophic containment failure in your water heater, causing an interior flood. Perhaps you change the toilet in an upstairs bathroom, and the new modern toilet is not providing enough water per flush to make the long run of the upstairs plumbing. So, it clogs up over time, then one day it backs up while you’re taking a shower, and you’re standing in multiple inches of grey water. Then the water does slowly drain, but you don’t notice that the pipe has cracked above the clog and it’s actually flooding into the room below, through the light fixture. Perhaps the main schedule 40 PVC pipe from the water main at the street slowly develops a crack, due to the roots of a tree nearby, and one day you discover that the water pressure in your house is really low and that you have flooded the whole street. Guess which of these have happened to us?
  - kazinator 2y ago
    All of them?
    - bradknowles 2y ago
      Correct in one!
  - kbenson 2y ago
    Mine were incorrect drainage outside, causing water to pool high enough inthe back yard that it came through the slider into the converted garage, soaking the pad and carpet there (in a few different locations actually), and the much worse one where a room was build off the same garage onto a concrete pad that was laid, but one of the walls was build on top of a covered deck that was build off the garage on one side, which had water run down it, hid the deck, then immediately go under the wall to the concrete pad meaning even moderate rains that didn't result in outside flooding would result in that room's pad and carpet getting wet and needing to be entirely removed, and the wall ripped out and rebuilt as it eventually was overtaken by mold. A large chunk of the house needed to be blocked off, industrial fans installed to dry it out, and then professionally redone. Building codes exist for reasons. Sometimes they seem frivolous, but often they're there for a damn good reason.
smallbluedot 2y ago
This sounds like a nightmare
opticfluorine 2y ago
I've ruled out several properties in my current homebuying search for this exact reason. Having lived next to the neighborhood collection pond once before (a rental thankfully), I'm extra paranoid about stormwater and drainage now. I've seen a number of homes in my area where the builder received special permission to build right where the drainage needs to go. Some were beautiful and I was tempted to give it a shot, but your story reminds me that I need to trust my gut on this issue and head for high ground.
swayvil 2y ago
House in shallow valley. Basically bottom of 3 hills. Multiple floods yearly. Basement pretty trashed. Beat it with 2 ditches, a drain, a berm and 2 pumps.
throwaway984393 2y ago
I live at the bottom of a valley, but luckily in a tiny house on a concrete pad, so I have no basement and I'm raised up two feet off the ground. That works pretty well for the house, but the driveway and yard still floods. So I dug a "pond" and small ditch things to channel water to it. You can't really tell where it is because I let my yard grow wild, but when it rains hard the water fills it up, and it evaporates/drains naturally over a couple days. The ditch actually speeds up the water drainage. I dug the ditches to divert the water around the property line, so the surface area of ditch in total is large, even though you can't really see it and it doesn't get in the way. I figure at least a quarter of the water drains through the ditch before it gets to the pond. This is probably helped by the fact that the soil is very rocky.
01100011 2y ago
I'm going to say that the vast majority of homeowners are not paranoid enough when it comes to buying their home. It is a huge investment and comes with very high transaction costs yet most people seem to make the decision based solely on superficial aesthetics.
- illiac786 2y ago
  What would you recommend noobs do, when buying a house? I guess hiring an expert would be the recommended approach, but all “experts” I have seen were all almost as superficial as I was - one literally assessed the wrong house. I’d pay good money for a good one, but it’s hard to find.
  - 01100011 2y ago
    Find an aggressive home inspector that isn't associated with your realtor, preferably one with general contractor experience and someone who is older. Like it or not, older folks have seen more things go wrong in more ways and can spot problems that younger folks might not be familiar with.
    - 486sx33 2y ago
      I have certification of an inspector with various home things… Flooring, roofing, general home inspection.. no one wants to pay what it’s worth so I don’t practice that, it’s just fun for learning about the building trades Further - if you never have a problem the value of the inspection is zero. If you do have a problem the value of an inspection after the problem has occurred is minimal. The value of an inspection that prevents a problem is something - but how to quantify that is difficult.
      - theGnuMe 2y ago
        You quantify it using a binomial. Then calculated the weight averaged expense repair cost using that binomial.
  - 10u152 2y ago
chiph 2y ago
20+ years ago, I had moved into a newly built home. And the first serious rain we got, I had water come into the living room (flooded the porch and seeped under the door). There was no insurance coverage since it was "surface water" and thus excluded. So I had to use a shop-vac and rent a couple of blowers to dry it out. There was a ditch out back but it obviously wasn't deep enough. I did the math and ended up with an astounding amount of water flowing by (something like 20,000 gallons per minute[0]) and complained to the builder about it. They sent a couple of guys out there who installed two 4" corrugated drainage pipes and said it was good enough. When the next big rain happened, where those pipes emptied out there was a 3 foot tall fountain of water from the pressure. It was an amateur Bellagio, lol. The yard still flooded but luckily didn't come into the house again. Since then, the landscaping came in throughout the neighborhood which controlled the runoff. But it taught me a lot of respect for getting slopes & drains right - Always use a larger pipe than you think you'll need. [0] The formula seems to be: V = 0.408 × Q/(D^2) where V is velocity in feet-per-second, Q is the flow rate in gallons-per-minute, and D is the diameter of the pipe in inches. I estimated the diameter based on the land profile that was underwater, and timed the velocity by following twigs/leaves floating by.
- SonOfLilit 2y ago
  You probably got a bit higher number than the true one, because water flows faster the farther it is from the floor/wall, and leaves float so they move like the fastest water, not the average water.
- 486sx33 2y ago
  This is called “overland water” and “overland water coverage” in insurance speak. It is usually not even offered as additional coverage.
  - alliao 2y ago
    I've visited Lloyd's Building on a building tour once, and seeing the scale and sheer floors of actuaries with PhDs in god knows what domain made me a firm believer in the real life prowess of the insurance industry. I honestly don't think consumer insurance is worthwhile, but commercial definitely if you have an equally capable team of actuaries to run the numbers and they stack up to cover the risks involved.
GiorgioG 2y ago
Sorry to hear of your troubles. We live in Holly Springs, NC not far from Cary. When our builder was showing us land/lots that were available at the time they only had lots that had driveways that would pitch towards the homes (in other words the road was higher than the house, not by much maybe 2-3 feet or so.) Of course developers and realtors always assure you it won’t be a problem - I was not reassured and so we passed on these lots. A few months later a lot became available that was well above street level. We’ve been here 10 years and never had an issue through heavy rains and even a couple of hurricanes. But we’ve met the neighbors who bought those properties with the driveway pitching towards their homes and they complain about having water coming into their garages whenever we get heavy downpours. If you’re going to live somewhere long enough that may experience heavy rainfall, it’s best to be well above the low end of the neighborhood/street.
aorloff 2y ago
And this is why if you own a very old house, you will notice is up on a hill
- peterclary 2y ago
  That isn’t my experience. We own a 15th C house which was originally a coaching inn beside the main road, which ran along the bottom of a hill.
phaedrus 2y ago
I have almost exactly the inverse situation. We are at the end of a cul de sac that is capable of efficiently draining water away and out of the neighborhood. But in roughly the spot where your drainage creek is, there's a large strip mall parking lot (across the street from our backyard). We don't get a lot of rain in annual total, but when it does rain heavily a flash flood comes into our backyard and must cross our side/front yard to drain into the cul de sac. The previous homeowner put in a DIY french drain, but either he didn't do it right, or it's too flat, or it's too small, or it is clogged. We instead get surface water flow and erosion along the same path where the french drain runs. (It doesn't help that when our neighbors got sand delivered for an above ground pool bed, the delivery truck dumped the entire pile of sand ON TOP OF the river rock exit basin for our french drain. The sand was later removed/used but I was still upset; unfortunately it was my brother in law who ordered the sand. Since the drain is above it I don't think it went in the drain, but maybe this rock basin was supposed to be a dry well.) I am thinking of building something like your concrete berm along my back fence line, possibly modifying the french drain to just transfer the water from the far side of the berm to the exit over the cul de sac rather than trying to absorb it from the ground.
- theGnuMe 2y ago
  Sand above the french drain isn't the end of the world, in fact some people prefer it.
eitally 2y ago
Too late to edit, but I realize I should have shared photos/videos for full effect: https://photos.app.goo.gl/kUmuhyNVXCXdTLH67 https://photos.app.goo.gl/kUmuhyNVXCXdTLH67
tomcam 2y ago
What nightmare. Sorry that happened to you.

kbenson 2y ago

One of the prior houses I lived at had so much flooding and water leakage problems from poor construction (prior additions that weren't strictly legal) that lead to carpet and padding having to be removed from concrete floored rooms and eventually mold problems, that when I bought a house a few years after we'd ran away from that disaster of a house we made absolutely sure to my at the high point of the (new) neighborhood so we weren't in the drainage path for anyone. It's particularly demoralizing to see the scope of the problem when it's all that water flooding your property and know there's nothing you can do in the short term, and even the long term is just trying different things and hoping they work, knowing that it will probably take a few tries.

bradknowles 2y ago
Flooding can come in many forms. Perhaps the balcony over your front door is not properly constructed and is not properly shedding rain, so one day during a torrential thunderstorm you suddenly have a flood coming in OVER your front door. Perhaps your water heater pan is not draining correctly, and one day you have a catastrophic containment failure in your water heater, causing an interior flood. Perhaps you change the toilet in an upstairs bathroom, and the new modern toilet is not providing enough water per flush to make the long run of the upstairs plumbing. So, it clogs up over time, then one day it backs up while you’re taking a shower, and you’re standing in multiple inches of grey water. Then the water does slowly drain, but you don’t notice that the pipe has cracked above the clog and it’s actually flooding into the room below, through the light fixture. Perhaps the main schedule 40 PVC pipe from the water main at the street slowly develops a crack, due to the roots of a tree nearby, and one day you discover that the water pressure in your house is really low and that you have flooded the whole street. Guess which of these have happened to us?
- kazinator 2y ago
  All of them?
  - bradknowles 2y ago
    Correct in one!
- kbenson 2y ago
  Mine were incorrect drainage outside, causing water to pool high enough inthe back yard that it came through the slider into the converted garage, soaking the pad and carpet there (in a few different locations actually), and the much worse one where a room was build off the same garage onto a concrete pad that was laid, but one of the walls was build on top of a covered deck that was build off the garage on one side, which had water run down it, hid the deck, then immediately go under the wall to the concrete pad meaning even moderate rains that didn't result in outside flooding would result in that room's pad and carpet getting wet and needing to be entirely removed, and the wall ripped out and rebuilt as it eventually was overtaken by mold. A large chunk of the house needed to be blocked off, industrial fans installed to dry it out, and then professionally redone. Building codes exist for reasons. Sometimes they seem frivolous, but often they're there for a damn good reason.

smallbluedot 2y ago

This sounds like a nightmare

opticfluorine 2y ago

I've ruled out several properties in my current homebuying search for this exact reason. Having lived next to the neighborhood collection pond once before (a rental thankfully), I'm extra paranoid about stormwater and drainage now. I've seen a number of homes in my area where the builder received special permission to build right where the drainage needs to go. Some were beautiful and I was tempted to give it a shot, but your story reminds me that I need to trust my gut on this issue and head for high ground.

swayvil 2y ago

House in shallow valley. Basically bottom of 3 hills. Multiple floods yearly. Basement pretty trashed. Beat it with 2 ditches, a drain, a berm and 2 pumps.

throwaway984393 2y ago

I live at the bottom of a valley, but luckily in a tiny house on a concrete pad, so I have no basement and I'm raised up two feet off the ground. That works pretty well for the house, but the driveway and yard still floods. So I dug a "pond" and small ditch things to channel water to it. You can't really tell where it is because I let my yard grow wild, but when it rains hard the water fills it up, and it evaporates/drains naturally over a couple days. The ditch actually speeds up the water drainage. I dug the ditches to divert the water around the property line, so the surface area of ditch in total is large, even though you can't really see it and it doesn't get in the way. I figure at least a quarter of the water drains through the ditch before it gets to the pond. This is probably helped by the fact that the soil is very rocky.

01100011 2y ago

I'm going to say that the vast majority of homeowners are not paranoid enough when it comes to buying their home. It is a huge investment and comes with very high transaction costs yet most people seem to make the decision based solely on superficial aesthetics.

illiac786 2y ago
What would you recommend noobs do, when buying a house? I guess hiring an expert would be the recommended approach, but all “experts” I have seen were all almost as superficial as I was - one literally assessed the wrong house. I’d pay good money for a good one, but it’s hard to find.
- 01100011 2y ago
  Find an aggressive home inspector that isn't associated with your realtor, preferably one with general contractor experience and someone who is older. Like it or not, older folks have seen more things go wrong in more ways and can spot problems that younger folks might not be familiar with.
  - 486sx33 2y ago
    I have certification of an inspector with various home things… Flooring, roofing, general home inspection.. no one wants to pay what it’s worth so I don’t practice that, it’s just fun for learning about the building trades Further - if you never have a problem the value of the inspection is zero. If you do have a problem the value of an inspection after the problem has occurred is minimal. The value of an inspection that prevents a problem is something - but how to quantify that is difficult.
    - theGnuMe 2y ago
      You quantify it using a binomial. Then calculated the weight averaged expense repair cost using that binomial.
- 10u152 2y ago

chiph 2y ago

20+ years ago, I had moved into a newly built home. And the first serious rain we got, I had water come into the living room (flooded the porch and seeped under the door). There was no insurance coverage since it was "surface water" and thus excluded. So I had to use a shop-vac and rent a couple of blowers to dry it out. There was a ditch out back but it obviously wasn't deep enough. I did the math and ended up with an astounding amount of water flowing by (something like 20,000 gallons per minute[0]) and complained to the builder about it. They sent a couple of guys out there who installed two 4" corrugated drainage pipes and said it was good enough. When the next big rain happened, where those pipes emptied out there was a 3 foot tall fountain of water from the pressure. It was an amateur Bellagio, lol. The yard still flooded but luckily didn't come into the house again. Since then, the landscaping came in throughout the neighborhood which controlled the runoff. But it taught me a lot of respect for getting slopes & drains right - Always use a larger pipe than you think you'll need. [0] The formula seems to be: V = 0.408 × Q/(D^2) where V is velocity in feet-per-second, Q is the flow rate in gallons-per-minute, and D is the diameter of the pipe in inches. I estimated the diameter based on the land profile that was underwater, and timed the velocity by following twigs/leaves floating by.

SonOfLilit 2y ago
You probably got a bit higher number than the true one, because water flows faster the farther it is from the floor/wall, and leaves float so they move like the fastest water, not the average water.
486sx33 2y ago
This is called “overland water” and “overland water coverage” in insurance speak. It is usually not even offered as additional coverage.
- alliao 2y ago
  I've visited Lloyd's Building on a building tour once, and seeing the scale and sheer floors of actuaries with PhDs in god knows what domain made me a firm believer in the real life prowess of the insurance industry. I honestly don't think consumer insurance is worthwhile, but commercial definitely if you have an equally capable team of actuaries to run the numbers and they stack up to cover the risks involved.

GiorgioG 2y ago

Sorry to hear of your troubles. We live in Holly Springs, NC not far from Cary. When our builder was showing us land/lots that were available at the time they only had lots that had driveways that would pitch towards the homes (in other words the road was higher than the house, not by much maybe 2-3 feet or so.) Of course developers and realtors always assure you it won’t be a problem - I was not reassured and so we passed on these lots. A few months later a lot became available that was well above street level. We’ve been here 10 years and never had an issue through heavy rains and even a couple of hurricanes. But we’ve met the neighbors who bought those properties with the driveway pitching towards their homes and they complain about having water coming into their garages whenever we get heavy downpours. If you’re going to live somewhere long enough that may experience heavy rainfall, it’s best to be well above the low end of the neighborhood/street.

aorloff 2y ago

And this is why if you own a very old house, you will notice is up on a hill

peterclary 2y ago
That isn’t my experience. We own a 15th C house which was originally a coaching inn beside the main road, which ran along the bottom of a hill.

phaedrus 2y ago

I have almost exactly the inverse situation. We are at the end of a cul de sac that is capable of efficiently draining water away and out of the neighborhood. But in roughly the spot where your drainage creek is, there's a large strip mall parking lot (across the street from our backyard). We don't get a lot of rain in annual total, but when it does rain heavily a flash flood comes into our backyard and must cross our side/front yard to drain into the cul de sac. The previous homeowner put in a DIY french drain, but either he didn't do it right, or it's too flat, or it's too small, or it is clogged. We instead get surface water flow and erosion along the same path where the french drain runs. (It doesn't help that when our neighbors got sand delivered for an above ground pool bed, the delivery truck dumped the entire pile of sand ON TOP OF the river rock exit basin for our french drain. The sand was later removed/used but I was still upset; unfortunately it was my brother in law who ordered the sand. Since the drain is above it I don't think it went in the drain, but maybe this rock basin was supposed to be a dry well.) I am thinking of building something like your concrete berm along my back fence line, possibly modifying the french drain to just transfer the water from the far side of the berm to the exit over the cul de sac rather than trying to absorb it from the ground.

theGnuMe 2y ago
Sand above the french drain isn't the end of the world, in fact some people prefer it.

eitally 2y ago

Too late to edit, but I realize I should have shared photos/videos for full effect: https://photos.app.goo.gl/kUmuhyNVXCXdTLH67 https://photos.app.goo.gl/kUmuhyNVXCXdTLH67

tomcam 2y ago

What nightmare. Sorry that happened to you.