500 year flood plain - How bad is this ? (Jersey City, Rahway: mortgage, how much)

[lets_hope_for_newbruns]

500 year is low risk.

if it bothers you so much -- just get sump pump installed if the basement does not have one already.
in fact you can install more than one sump pump if you have a large basement.

[splitchin]

Originally Posted by lets_hope_for_newbruns

500 year is low risk.

if it bothers you so much -- just get sump pump installed if the basement does not have one already.
in fact you can install more than one sump pump if you have a large basement.

Thanks for sharing that info. Yes it does already have a sump pump in the basement.

Actually, the possibility of flood does not concern me as much and it is very likely that we may not have to pay flood insurance either as the current owners are not required to pay any by their lenders

But I am concerned about resale value. This section of the town is the starter section and we would very likely sell this to first time buyers like us who are not very knowledgeable. Their reaction will be probably be negative like ours. So I think it will hard to sell this property in the future.

[hmalib]

Originally Posted by goonsquad

Are there flood plain maps for NJ?

I have been using this 2 sites to check for flood zones. Might be helpfull for you as well.

www.floodsmart.gov
and
FEMA Map Service Center -

Henryk

[Ninjahedge]

Bottom line that most people misunderstand is a 500yr flood IS bad, but it just means that the mean time for recurrence is 500 years.

A bit of information on flooding probability:
Why you can get '500 year floods' two years in a row : Highly Allochthonous (http://scienceblogs.com/highlyallochthonous/2008/06/why_you_can_get_500_year_flood.php - broken link)

Comment #1:

The probability of a 500-year event occurring exactly once in a year is more like 0.001998 (not quite 1/500) if you assume it is a Poisson process. For two occurrences in 15 years the probability is 0.0004358.
We use the Poisson model for earthquakes; I don't know if it applies to floods.

Technical information on the formulas used for calculating and setting these probabilities (seismic):
Foundation Design Codes and Soil ... - Google Book Search

(warning, VERY technical!!!!!!)

The probability for a 500 year storm occuring in any one year is around 0.2%

If you use the graph on the more technical page you can see the cumulative chance of having one during the time you are there (just look at the ratios on the top of the graph. When it reaches "1" it means you have reached the time period specified. So figure you live there for 50 years, chances are 10% (look for 0.1 on the top bar, then follow it across to the numbers on the right. It is about 2.5 lines up, and each line is 4%. 4% x 2.5 = 10%)

Sorry if I confused anyone with that.


Bottom line is to look around the house. Look at the trees, see if you can see any flood lines on them. Look for the same in the basement. Look for driftwood. Ask about any streams in the area. Look at the lay of the plot. Is it in a hollow, or even with the houses around it? Is it slightly elevated compared to the ones around it? Look in the news, has it flooded there recently and why? (dam overflow, storm drain clogage, etc)?

Hope this helps!

[splitchin]

Thanks much for the extensive information !

[millsan1]

Our basement in Paramus flooded twice, both times during long nasty rains. It was a finished basement. We just replaced the carpet with tile and hung the sheetrock with a 2 inch gap to the floor and put in tall floor molding. Looks great and if it floods again, we are fine.

[splitchin]

Originally Posted by millsan1

Our basement in Paramus flooded twice, both times during long nasty rains. It was a finished basement. We just replaced the carpet with tile and hung the sheetrock with a 2 inch gap to the floor and put in tall floor molding. Looks great and if it floods again, we are fine.

Thanks, we are looking in the same area (northern bergen county) around route 17.

Is your home in a flood plain ?

[millsan1]

no, but as others have said, with all the development going on, a lot of those maps are inaccurate. Developments take away the ability of the land to absorb the rains.

[dexitz]

Originally Posted by splitchin

Yes, there are flood plain maps for this area that clearly show the property in a flood plain.

Where did you obtain the flood plain maps from? Interested in obtained some myself.

[splitchin]

My realtor gave me a map in a PDF file format.

These links were posted by someone earlier:

FEMA Map Service Center -

Floodsmart.gov: Your premier resource for flood insurance information