The city sewer backed up last September and flooded our basement with a foot of rain water. I want to prevent that from happening again, so I'd like to install some sort of flood control. I've been given several different options by several different plumbers, but none of them could really state why their method was the best.

1) External flood control in front yard - $7000
2) Internal flood control connected to catch basin - $3500
3) Internal flood control connected to "stack" - $3800

I like option 1 because I understand it, but it's so expensive! Also, since the sump pump is in the front yard, we would have no way of knowing when it failed until it backed up.

It's the other two options that I don't quite understand. In both cases, the plumbers said they would redirect all our basement plumbing (the floor drain, the basement sink, etc.) to a new sump hole and pump everything out. There would be no backup because the pump out line would have a valve on it. But one guy said he'd have it pump back out to the catch basin, and the other guy said he'd connect it to the "stack".

Is there any reason one method is better than the others?

I'm concerned about too much water collecting in the catch basin - it is only 3 feet from our back wall and that wall already has a lot of seepage. And I don't understand the stack at all - where does that go? Does it connect to the main sewer line below our house? And is there a problem with having the valves inside? One plumber said he'd go with the external flood control because if water fills the sewer line that runs under our basement the pressure could crack our floor!

I have asked all of them to explain why their method is better, but none of them seems to be able to explain it very well.

Any help would be greatly appreciated!

Milo Dolezal

Thanks for your detailed explanation.

I think your plumbers are proposing little too much to do, perhaps we could call it "overkill". Especially, since this is not repeating problem.

I would install Sewer Check Valve someplace before your sewer pipe connects with the City Sewer. Of course, this installation should be on your property, between the curb and your house.

It is quite simple installation. Excavating and exposing your sewer line is the most time consuming work. Installing the Check Valve should take no longer than 1 hour.

Now, you are saying this pipe "....goes under the house and connects to the city line in front ..." Question: Is this pipe accessible and /or exposed somewhere under your house - and before it leaves your house ? If it is, it can save you the labor on digging. Please, let me know ... Thanks.... Milo

( FYI: I will be on the road all day tomorrow coming back late in the evening....)

speedball1

Do I even need to go into a technical explaination why this is a load of crap?:?
Let me repeat my recommendations;

If zgeist has a bathroom group in his basement a sewage back flow preventer, (see image ) would be then way to go, however i9f all he has is a washer and floor drain then I'd install Flood Guards,(see image) on the floor drain. The estimates given are way outta line in my opinion. Good luck,Tom

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ballengerb1

I'd be interested in reading what you found about dangers of a stand pipe. No such thing exists to my knowledge. There will be absolutely no more pressure with a stand pipe than without. A standard poured floor would not be in danger either.

zgeist

I found several sources online that said your floor could crack an even heave up if you used a stand pipe or plugged up the drain. I don't really understand why this would or would not happen (so a technical explanation would actually be appreciated!). The third plumber I had come in said he'd seen floor heaved up as much as 16"! I hope you understand why that would alarm someone with no knowledge of plumbing. :-)

I will try to find my online sources and post them here tonight when I have more time to use the Internet. Thanks for all you helpful replies.

zgeist

I do not have a bathroom in my basement - just a washer and sink. Although I have considered installing one...

ballengerb1

I should have asked this question long ago, how much standing water entered from the flood.

speedball1

That was the Seven Grand Plumber that said that, huh?
Ya wanna a "technical explanation" ? Would a "common sense explanation " do
You failed to tell us what material your pipes were so I'll go with both 4" Cast Iron and PVC.

4" PVC will burst at 710 PSI and has a max working pressure of 133 PSI while Cast Iron has a max working pressure of 250 PSI. ( Didn't give a burst pressure.)
Let's say that you had nothing open in your basement and the water backed up to your first floor. ( I realize this could never happen but that makes as much sense of the pipes blowing up through the cement,) So you have a backup exiting outta the first floor shower. That would give you about a 12 foot head of water. At .434 PSI a foot that would give you a little over 5 PSI pressure on the pipes under the pour.
Can you see how silly the statement the plumber made sounds to me?
$hit can the plumbers that want to vacation at Club Med or Aruba on your dime.
You've been given excellent advice on this page. I'd listen to it. Good luck, Tom

zgeist

Our entire basement floor was covered with about 6-8" of water (the basement is not completely level). It came up to the first step on the stairs.

For those that asked where I read that basement floors could crack, here are a few references (I'm not trying to contradict anyone - it's just that someone asked for this info):

A website that sells the Flood Guard (The Mechanicals - Basement Flood Prevention - Keidel Bath, Plumbing, Kitchen - Cincinnati, OH) says of the standpipe model: "However ... in extreme cases, rising water in an excessively tall standpipe may create enough pressure in the home's sewer line to rupture pipe joints under the basement floor." - but I not they don't state what is considered an 'extreme case'.

A website for the city of Wood Ridge Illinois that describes different methods of flood protection (Steps to Protect Your Property, Flood Information, Wood River, Illinois (IL)) says "using standpipes over 12 inches tall or capping a standpipe may rupture sewer pipe joints under the basement floor."

I appreciate the suggestion of the flood guard drain plug - that is an extremely cheap measure that I had not heard of before! Can't imagine why none of my plumbers mentioned it. :-)

I like the check valve idea, too - we have a weird pit in our basement floor about 6 feet from the front wall - it looks like it might have once been a sump pit, or provided access to the sewer line, but the bottom has since been sealed. Perhaps a check valve could be installed there?

speedball1

I challenge both web sites to come up with more then just words telling us that a stand pipe over 12" high could possibly burst pipes or joints under the basement floor.
In a earlier post I laid forth the facts, I see no explanation in either website that tells me exactly what would cause drainage pipes to explode upwards outta the basement floor. No facts! No explanation!
I wanna know where they came up with the warning and how they justify it.
Regards, Tom

hkstroud

Tom,
You know that people write articles for one reason, to get them published. To do that they must say something different than has already been said. What will get your article more widely read than some kind of warning? If facts and logic get in the way, that's just too bad.