Water Tables, Flooding, Home Purchase (Huntsville, Decatur: insurance, mortgage, house)

[Charles]

We are looking to purchase a home in the Huntsville area. I have heard and read about potential problems with flooding, flood plains, water tables, etc.

I have several questions.

How do I find out if a particular house I am interesting in buying is vulnerable to water table problems or flood plain type risks?

Who do I ask? Insurance company agents? Do they have maps and data to identify risky homes? What about USGS resources? Madison County resources? Are there general guidelines or certain areas?

How should I approach this? What have the wise folks on this board done when they bought their homes? How did they do the research? Is there a simple way to do this?

How would you complete this sentence "Because of the risk of water damage due to water tables or flood plain issues, I wouldn't buy a house that...."?

I am a pretty risk averse person, pretty conservative and I think I own every type of insurance known to man, so don't hesitate to deliver a bunch of "What if"s.

Thanks

[flstatenolefan]

IMO, it doesn't matter what the tables say regarding flooding. It can happen to anyone. My parents built out of the 100 year flood plan and were flooded when the Pea River dam burst. They lived in north Florida, the dam was in Alabama. All the water had to go downstream somewhere. That was supposed to have been an exceptional occurrence, but they were flooded again 4 years later. They left and built elsewhere after that flood.

Yes, by all means check with the county to see where the flood plains are, but regardless, purchase flood insurance. Your pipes can burst and flood your home, so it's always a possibility no matter where you live.

[Scupperer]

You can find a lot of information, including flood zones, on any property in Huntsville here:

City of Huntsville Interactive Maps:
City of Huntsville Interactive Maps

It works best in Internet Explorer.


One of the concerns regarding purchasing a house in a flood zone isn't necessarily the flooding, but the limitations of what you can do with the property, due to new FEMA rules that the City has adopted.

If the structure meets all FEMA flood zone requirements, there's a special certificate that can be issued that kind-of exempts the structure from the flood zone. Ask for that from a previous owner - it will certify that the floor of the house is at least 1 foot above flood elevation. If there is a crawl space within the flood zone, it should be specially vented for water. A couple of other requirements as well.

If the property doesn't have this, then if in the future you go to make any changes to the property that require a permit, the Engineering Department will require an appraisal of the structure, and you'll be limited to only improving/adding up to 50% of the value of the existing structure. That value is fixed over time based on the original appraisal you submit, and does not adjust.

Once you reach that 50% value, you can do no further modifications of the property until all structures on the property are in full compliance with FEMA flood zone requirements. In many cases, this can involve lifting a structure up to bring the floor up to 1' above the flood elevation. In some cases, it's not economically feasible to bring the existing structure into compliance.

If the previous owner has done any permitted work within the last 10 years, then the City will already have an appraised value of the house, as well as what work towards that 50% has already been completed, or if any upgrades to make the property flood zone compliant have happened. So, you need to know. You can probably call the Engineering Department directly and ask, if you don't trust an agent or they just don't know.

[TimG]

Normally the MLS listing mentions in the remarks field when flood insurance is required if there is a prior history. However, this information is not extremely reliable in other circumstances.

The FEMA flood zone maps do provide some general area information: FEMA Flood Maps

Nevertheless, when it comes to a particular locale or address it is best researched through the listing agent/previous finance company if you would like to know if flood insurance was a mortgage requirement.

If it is, then a new policy would certainly be warranted! If not then a study of local flood maps may be in order: City of Huntsville Interactive Maps

However, I am not a professional who is capable of giving a recommendation of when to obtain flood insurance or not, finance companies do mandate such, based on current conditions. But if you decide on a local neighborhood with a mountainous drainage valley, it would never hurt to have such coverage to protect your investment.

Regards,

Tim

[Charles]

What about water tables, or (if I understand this correctly) the tendency for the ground to become saturated and contribute or cause some damage to the home? Maybe the house isn't in a flood plain or subject to flooding from an overflowing stream or river but can the property turn into a swamp or something and oversoak the undersides of the home? Not sure if my questions are even valid.....but it is something I thought I heard or read.....

[Scupperer]

Originally Posted by Charles

What about water tables, or (if I understand this correctly) the tendency for the ground to become saturated and contribute or cause some damage to the home? Maybe the house isn't in a flood plain or subject to flooding from an overflowing stream or river but can the property turn into a swamp or something and oversoak the undersides of the home? Not sure if my questions are even valid.....but it is something I thought I heard or read.....

In this area, your big concern with soil saturation would be on a sloped development. Heavy rains on a hillside can weaken the soil and threaten improperly built foundations. I don't know exactly when the city began requiring engineered foundations on sloped developments, but it's been for at least 10 years. I recall that Mayor Spencer had a bit of concern with the possibility of her house sliding off the mountainside a while back...

Another concern is sinkholes - a lot of the bedrock in this area is limestone. I don't believe there's any way to predict them, though, and they're rare.

In most other areas, the soil usually isn't tested for residential construction; it's just assumed a good stiff clay will be a foot or two down, and if you hit bedrock, you work with it or around it. The clay here generally is not expansive clay, where saturation would cause considerable problems with a foundation and require specialized design (see: Swelling Clays Map - Risk Areas (Consumer)).

Typically, standard steel reinforcements for concrete and masonry are enough to withstand any variations in the clay due to moisture content, in this area.

I'm an architect, so my experience with foundations and soils is limited, but these are the primary soil/foundation considerations I've dealt with. If in doubt over anything, always get a soil analysis. You might also try calling the city and see if they have any soil tests on record in the vicinity. The city often does soil tests for road work or underground utility projects, and since subsoil conditions don't change a great deal over time, the age of the report isn't necessarily important (unless you plan to build something new).

[Southlander]

Originally Posted by Scupperer

e age of the report isn't necessarily important (unless you plan to build something new).

Good advice Scupperer, thanks for posting!
A soil analysis is fairly easy, but I'm thinking it might be more and more important to get a geologic analysis. How do you do that?
There are a couple of subdivisions being built in the Decatur area that I question. I've been here for 40 years, so I know those areas are prone to sinkholes or have underground streams. But people new to the area don't know that.
I have to question why the city let them build there (in one case - the other subdivision is in the county, which has looser or no requirements). But we're all learning you can't count on governments anymore to protect people from unscrupulous developers.
So...how would you go about getting a geologic survey? Have you ever had to do that?

[Scupperer]

Originally Posted by Southlander

Good advice Scupperer, thanks for posting!
A soil analysis is fairly easy, but I'm thinking it might be more and more important to get a geologic analysis. How do you do that?
There are a couple of subdivisions being built in the Decatur area that I question. I've been here for 40 years, so I know those areas are prone to sinkholes or have underground streams. But people new to the area don't know that.
I have to question why the city let them build there (in one case - the other subdivision is in the county, which has looser or no requirements). But we're all learning you can't count on governments anymore to protect people from unscrupulous developers.
So...how would you go about getting a geologic survey? Have you ever had to do that?

For construction purposes, a soil analysis usually includes a geologic summary of the area, in order to assess risks of sinkholes, dormant springs, or other surprises. This may not be true with information from a soil test done for specific utility/road purposes, though.

If you're familiar with how to read geologic surveys and know specifically what to look for, you can always go to Welcome to the USGS - U.S. Geological Survey, where a lot of info is available for free, and even more if you're willing to spend a little money. I've never used it for this purpose, but I have for topography.

If not, and you don't have a specific sight, but just want information on general areas, your best bet might be to take a geologist or soils engineer out to lunch

[marysally]

A number of years ago when I lived in Houston (near Clear Lake) a tropical depression dumped a Guiness record amount of rain in our area resulting in 3 ft of creek water in our house. Fortunately we had flood insurance although we were outside the 100 year flood plain and the little meandering creek which reached a mile wide at its peak was normally three block away from our house. Although we were able to repair the house after a lot of hard work, we never lived there again. I also would never buy a house where flood insurance was required -- that is just asking for trouble. My criteria is always to buy the house with the highest elevation and never buy a house at the bottom of a sloping street.