Sewage Check valve - combating the city's sewer system

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Chefwong

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I get backup coming out of the toilet, shower, etc in the basement when it rains HARD and the sewer just keep up with the water.
It's not just localized to my house but I suspect all the houses on the block. Couple of neighbors to the right or left of me, all have this issue.

For the 3 or 4" branch in the floor, if I gut it and put a DWV check valve in it, will this ultimately stop/prevent the backup that comes from the lowest point in the house...


Are there rough in access boxes - similar to access panels, that one uses for the floor, so that when you repour to to cover the pipe, the checkvalve is accessible ?
 
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Jadnashua

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One would think that a checkvalve, being a fairly simple device, would be quite reliable, but considering what goes by it, they don't always work reliably. It may be worth a shot, but it's not a guarantee.
 

Chefwong

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One more note.
Any preferred brands/designs.

As well, any CONS to this your guys see in the real world ?
It will be a horizontal setup....
 

hj

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severaal "cons". When the sewer system is backed up, you CANNOT use any water in the house or THAT water will flood your basement. If ANYTHING gets stuck in the valves mechanism, the backup will still occur, it will just happen slower. a good plumber can design a backwater valve/pump installation to keep the good features and eliminate the bad ones.
 

Jadnashua

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Gravity is the cheapest way to drain anything, but as HJ was alluding, if you added a sewage basin and ejector pump, running the outlet high enough, it would be unlikely to backup AND you could still pump your waste into the sewer. The added complexity, maintenance, and costs may be worth it to you, or not.
 

Chefwong

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It has not happened in the last 8 years if I had to guess. Some neighbors have it more worse than others (meaning some have it yearly).
It just so happens that it happened during Irene as well as about 2 weeks back when we got 10 inches of rain in a short amount of time.

IF I had to guess, I had at least 60-90 gallons on the backup. I calculate this as I closed the drain on the tub, and was using a 2 utility pumps to fill the tub. As the tub got full, I disconnected the sump, and put the sump in the tub, which made quick work on getting the water out of the house..

I've never had a sewage basin/ejector pump so I'm on the bench on having a extra complexity in the mix. Sure things can fail.....so what's worse --- the cleanup/catchup of not having a system like this in place.

I found this while googling yesterday. I was thinking this would be on the main stack already in the floor with a access panel on the floor once everything was buttoned up.
http://www.youtube.com/watch?v=FMBznnNV-ss&feature=related

My only issue with this is aside from when it's raining, I know I can look inside the access panel to confirm the checkvalve is in effect.
I suppose the huge drawback is that god forbid someone uses the toilet and the checkvalve is in effect...
 

Chefwong

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One more note. Bearing the basement is the lowest spot in the house....the sewer backflow occured here.

The main floor/second floor is coming off a WYE off the main. Basement runs one direction, the 1st floor and second come off another.
IF I had the checkvalve/sewer ejector setup in the basement bathroom ----- I would still need a checkvalve on the 1st floor vertical stack .

Whereas in the checkvalve link I posted in the other thread, if it came right off the main entrance point, it serves the entire DW system for the house.
 

hj

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pump

I would NOT install an ejector pump for the whole house unless it was a $6,0000.00 system with all the necessary bells and whistles. I would install the backwater valve and then a "side arm" pump to handle the temporary water issue.
 

Kentd

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One more note. Bearing the basement is the lowest spot in the house....the sewer backflow occured here.

The main floor/second floor is coming off a WYE off the main. Basement runs one direction, the 1st floor and second come off another.
IF I had the checkvalve/sewer ejector setup in the basement bathroom ----- I would still need a checkvalve on the 1st floor vertical stack .

Whereas in the checkvalve link I posted in the other thread, if it came right off the main entrance point, it serves the entire DW system for the house.

I don't understand why you would need a checkvalve on the 1st floor vertical stack. Are you worried about water from the street line backing up into the first floor fixtures? I'm trying to imagine the situation where the storm or sewer backs up into a first floor fixture without there being massive flooding in your yard, or the street, or the main floor of the house for that matter. If it has backed up into the first floor, wouldn't it also be coming up through manhole covers in the street?

I would think putting the backflow valve on the drain serving the basement fixtures while leaving the 1st floor stack unchanged would be your best bet. I'm making a similar choice right now in my own basement, so I'm curious to know where my thinking is going wrong.
 

Chefwong

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Unless I am looking at this wrong, when it backflows....the point where *it's releasing the backflow* starts from the lowest point in the house.
Now if I have that stopped on the basement side , that buildup still has to go somewhere - so it continues on till it goes to the next level of release.
 

hj

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True, BUT that next point of release still has be at the same level as the backed up water in the main sewer. IF your upper level is HIGHER than the manholes in the street, the water will flow out of them LONG BEFORE it will ever overflow your toilet. You will have advanced warning before it happens, because the water will be coming in under your doors and flowing across your carpet and tile.
 

Chefwong

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Got it HJ. The last post cleared things up a bit.
So even with a regular checkvalve setup in the basement ---- the higher outlets/ejector pump is a much more superior way to go from a design standpoint thatn just the checkvalve itself.
 

famattjr

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Not a pro-but I have a similar problem, have a backflow preventer in the line, it's got a one way flapper and a wheeled gate valve. I relied on the flapper this time, big mistake, either the surge overwhelmed it or something was stuck, I got a foot of sewer water. I forget the brand, but it's a major one, not a cheapie. You can't rely on the flapper. Earlier today I was looking around and found this one which is highly recommended elsewhere:

The problem with the one I have is that the flapper is not that reliable and you don't know when it is engaged. If you use water when the flap is engaged by pressure from the outside, water will then exit from your lowest points in the basement. Then you have to decide when to use the wheel to tighten down the gate valve. Mine is literally 34 turns.
 

Chefwong

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How much access is there to retrofit to a ball valve...famattjr

Wow. I've never really put thought into this flooding problem as it really never really affected us (my next door neighbor gets like 5 inches at least 3-4 times a year when it rains hard). Glad to hear famattjr's experiences on what has worked or not worked for him. Time to do more homework on the various check valves out there....unless you pros tell me to stop, don't look further and look at X brands...
 
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