Storm Sewer Backs-Up Into Basement

[sburtchin]

The storm sewer, sanitary sewer and municipal water supply all run parallel along the street in front of my house. My basement layout (44' x 28') is approximately as follows:

. +---------------------A--------FRONT--------------------------------+ .
. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .| .
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. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . B . . . . . . . . . . . . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . D . . . . . . . . . . . . . . . . . . . . . . . . . . . | .
. +--------------------------------------------------------------------+ .

"A" is where the municipal water enters the basement. "B" is where the stack for the toilets goes through the basement floor. "C" is the location of the floor drain. "D" is where the discharge from the washing machine goes through the basement floor.

My storm sewer use to empty into a drainage ditch about a half mile away. About 15 years ago a retirement community was built there. My storm sewer now empties 10 feet below the surface of a retention pond. In the last 7 years my basement has flooded three times. Each time less rain was required to cause the flooding, the water has gotten deeper each time, and it has taken longer for the water to drain back out.

The last time the water got to about 9" deep. The water in the basement toilet was several inches above that, even though no drains or toilets had been used after it started raining. Is there any connection?

The water bubbles up through the concrete floor, and gushes up through every crack in the floor, not just out of the floor drain. What are my options?

 

[Mr_David]

First , Storm and Sewer are 2 different things. But we understand.
Call it storm drain and sewer drain.

Your storm drain does what???
"My storm sewer now empties 10 feet below the surface of a retention pond"
That seems like you have a drainage problem but.

Going to need more info than that .

 

[sburtchin]

OK, my local government officials call it "storm sewer" and "sanitary sewer", but I understand.

"Your storm drain does what???"
My storm drain flows west along my street, then south about 1/2 mile where it use to empty into a ditch. My sewer drain flows to the sewage treatment plant north of me. I know they are supposed to be separate, but when the storm drain floods, the sewer always floods too. The last time it was less than an inch from the top of the toilet bowl rim in the basement.

The location where my storm drain exits has not changed. A retirement complex was built up around it consisting of about two dozen buildings spread out over 10's of acres. The ditch was widened in several places and a weir was constructed at the far end (of the retirement complex) to raise the water level by about 12 feet. These ponds are the focal point of the retirement community. My local government says these 'retention ponds' were built for our benefit to improve handling of storm water. They say the flooding is due to the unexpected biblical rains we have been getting over the past decade. I guess 4" in one day is now considered a biblical rain.

The flood water gushes up out of the floor drain and every crack in the floor. There has never been any significant seepage through the basement walls. When my basement floods, every house in the neighborhood that sits lower than mine also has basement flooding, and the ones sitting higher are OK.

Is there something else you need to know?

 

[Mr_David]

maybe if you installed a back water check valve or disconnect the drain altogether and install an ejector pump. Could be an obstruction in the drain downstream from you as well.

 

[sburtchin]

Where do I install the back water check valve? Can that be anywhere between the house and the street?

To disconnect the drain altogether, would I be correct in assuming that would be done between the perimeter tile and where the pipe passes through the foundation? Do I physically dig down to it, or can a plug be installed working from inside the basement? Please explain the process.

Is the ejector pump essential with either or both of these solutions? Where/how is it installed?

By an obstruction downstream, are you suggesting this might be 1000 or 2000 feet downstream? I suspect that sediment could be building up in that drain pipe because the exit point is under water.

 

[Mr_David]

dig up your drain outside the building. install a back flow valve.
It has to be accessible. so it can be serviced.
if the outlet end is below water line at pond it could very well be closing up with sediments.
I would disconnect it al together from my basement especially if that drain is shared with other homes.
Upper homes will drain into lower homes if drain is blocked
iNSTALL AN EJECTOR SYSTEM. you can pump out any water and not have to rely on a common drain. But if you loose power you need a battery back up.

 

[sburtchin]

In the diagram, the drain from the ground floor toilet appears to be connected to the output from the sump pump. Is that necessary, and what would be the purpose?

My house was built in 1965. The floor drain in the diagram connects to the drain from the basement toilet. I am certain mine does not connect in that way (never any noxious gases from that drain). You are suggesting I install an ejector system as shown in the diagram? That looks like it should cost well over a thousand dollars even if I do all the work myself. At the moment I don't see why that would be a necessary expense. There are more than 30 homes in my neighborhood that sit lower than mine. I have not heard mass outrage of huge amounts of raw sewage flowing into basements. I am sure few if any homes have an ejector system as described. I know my local government is concerned and actively pursuing improvements to handling of sanitary waste, so that should improve. What could be the cause of the water level rising in my basement toilet during these flood events? By my logic the basement toilets should be overflowing in every house lower than mine, but that doesn't seem to be happening, or they fail to complain.

 

[sburtchin]

In the following diagram, "A" is where the municipal water enters the basement. "B" is where the stack for the toilets goes through the basement floor. "C" is the location of the floor drain. "D" is where the discharge from the washing machine goes through the basement floor.

Can I assume the pipes for points "A", "B": and "C" flow directly from/towards the street? What depth relative to the basement floor should I expect to find pipes "B" and "C"? How certain would this estimate be?

. . . . . . . . . . . . . . . . . | . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . | . . . . . . . . | +-------------|----------------- .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . SIDEWALK .|. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . . . +-------|----------------- .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . . . | . . . . .|. . .. . . . . . . . . . . .
. +---------------------A-----FRONT-|---------------|-----------------+ .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . C . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . B . . . . . . . . . . . . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . D . . . . . . . . . . . . . . . . . . . . . . . . . . . | .
. +--------------------------------------------------------------------+ .

To disconnect the drain altogether from the city storm drain, I assume I should plug or cap pipe "C" somewhere between the perimeter tile and the street. Can I insert the plug from inside the basement, or do I have to dig? If I choose this option, can I put the sump pump at point "C"?

All the homes here share the same sanitary sewer and the same storm drain. The harder I press my local government for answers, the more I get an evolving web of lies and inconsistencies. The storm drain does exit at the bottom of that retention pond, something they will no longer admit to. They claim those ponds actually improve the removal of excess rain water.

 

[sburtchin]

To install a back flow valve to pipe "C", I assume this has to be somewhere between the perimeter tile and the street. If I dig beyond the sidewalk, I can use an excavator. If I have to dig next to the house, I would have to go through the sidewalk, or dig by hand. There is shrubbery in there too.

This area was a swamp. The soil is a dense hard clay. I know from experience that digging the undisturbed soil here by hand beyond 4' is not practical. Would digging next to the foundation be any easier?

By keeping the back flow valve accessible for service, do you mean I have to install a man hole that I can climb down into? What kind of service would it require?

 

[Mr_David]

My picture was just a random picture I found. I was referring to adding a pump just for the storm water. If it is not adequately draining during a storm then add a pump and pump it out. just pump it out to the curb and not to the over loaded or inadequate storm drain

 

[sburtchin]

If I dig a pit at point "C" in my diagram,

A) Would the water flow into it through the drain pipe at a sufficient rate to keep up with the water flowing in from the storm drain? Since the water gushes up through cracks in the floor, I am thinking that either the drain pipe is leaking under the floor or water is leaking around the drain pipe where it passes through the foundation, or both.

B) What capacity sump pump would I need?

 

[Mr_David]

the water is coming from cracks in the floor and the drain I would dig up the drain outside and brink it up to ground level. install a sump pit in the basement and run the discharge to the elevated drain. this way the common storm drain cannot ever back up into you basement. you can pump out ant ground water that is seeping up through the bottom due to saturated ground.
A backwater valve will only prevent water flowing from common system into your basement. but if it is saturated ground water it wont help.
they have some valves that have an extension to surface so you do not have to build an assess hole to them

http://www.backwater-valves.com/

 

[sburtchin]

the water is coming from cracks in the floor and the drain I would dig up the drain outside and brink it up to ground level. install a sump pit in the basement and run the discharge to the elevated drain. this way the common storm drain cannot ever back up into you basement. you can pump out ant ground water that is seeping up through the bottom due to saturated ground.

Point "C" in my diagram would be the most convenient place where I could install a sump pit. My basement is always dry with the exception of these flood events. Yet 10' from my house the water table is sometimes less than a foot below the surface. Can I assume my perimeter tile is in good working order?

I think what you are suggesting is that I disconnect and plug the pipe where it passes through the foundation, and that I DO NOT disconnect the perimeter tile from the city storm drain?

If the drain pipe can be plugged where it passes through the foundation, can I auger down to the perimeter tile to create the outside drain? I would guess I should hit a layer of stone before accidentally punching through the tile? (using seepage from the outside drain into the stone bed rather than a direct connection)

A backwater valve will only prevent water flowing from common system into your basement. but if it is saturated ground water it wont help.
they have some valves that have an extension to surface so you do not have to build an assess hole to them

Then I physically have to close the valve when I suspect a flood event might happen? When I am on vacation there would be no protection. And, I would still need a sump pump if the flood event lasts long enough for ground water seepage to become a problem?

Can I assume the pipes for points "A", "B": and "C" flow directly from/towards the street? What depth relative to the basement floor should I expect to find pipes "B" and "C"? How certain would this estimate be?

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. . . . . . . . . . . . . . . . . | . . . . . . . . | +---------------|---------------------- .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . SIDEWALK .|. . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . . . +--------|---------------------- .
. . . . . . . . . . . . . . . . . | . . . . . . . . | | . . . | . . . . .|. . .. . . . . . . . . . . .
. +-------------------------A-----FRONT--|-----------------|--------------------+ .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . | . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . . . . . . | . . . . . . . . . . C . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . B . . . . . . . . . . . . . . . . . . . . . . | .
. | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .| .
. | . . . . . . . . . . . . . . . . . . . D . . . . . . . . . . . . . . . . . . . . . . . . . . . | .
. +-------------------------------------------------------------------------------+ .

What would be the depth of the perimeter tile relative to the basement floor, and what distance between this tile and the foundation? Would the floor drain pipe be at a higher level?

 

[Mr_David]

I'm guessing the perimeter tile is what we call a French drain. A perforated pipe embedded in gravel around the perimeter of the subterranean wall (basement) this drain is connected to common storm water drain.
Obviously you have no control over the common storm water drain.
so once again you either install a back water valve to protect you from the common line from totally flooding you out.
Presuming your water table is always high then disconnecting it may not be a good thing. The perimeter drain is probably doing its job and the common drain is inadequate when the heavy rains come.
you need to consult an engineer maybe not a plumber. The plumber can fix or install you piping but you have others concerns to be addressed.
Water tables Actual discharge of the common storm drain.
Is the storm drain 100% clear??

 

[sburtchin]

Perimeter tile / French drain / weeping tile - a lot of people around here call it "perimeter tile", possibly slang or a holdover from when it was actually clay tile. My house was built in 1965. Maybe you would know what material was used then.

I dig a hole, ground water flows into it, I assume that's where the water table is. Maybe I'm assuming too much. This area was once a swamp. About 6 months of each year the ground is squishy. In the summer we have a drought and you may dig down 12' and find dry hard earth. My basement is always dry. I assume that at least 6 months of the year that French drain must be carrying away a lot of water.

"Is the storm drain 100% clear??"I suspect that it probably is not. The first time my basement flooded, we had heavy rains all week with total saturation and standing water everywhere. Then we had 7 more inches of rain in a 4 hour period. It flooded quickly, and within a few hours it all drained back out. Since they built that retirement community, it has flooded 3 more times, less rain was required each time, and now it takes about 24 hours to drain back out. Now if the ground is wet or frozen and I get more than 3 inches of rain I am sweating bullets. The last part of that storm drain pipe is always flooded, so I suspect that after each heavy rain, the flow gradually slows to a stop and deposits a lot of sediments that never get flushed out.

My local government is doing something with the sewer every month. I am skeptical of how hard they go at it. They rarely ever do anything with the storm drain. When people complain they say it's a matter of priorities. They claim it will cost between 25 and 50 million dollars to upgrade the storm drain system for our town of 1800 people. They suggest that every homeowner install a backflow valve in the middle of our front yards at our own expense.

My neighbor had some kind of valve installed under his basement floor. I got the impression that he had to manually close it when a flood was about to happen. He said it kept his basement dry (no sump pump). He payed the plumbing contractor $800 about 7 years ago. I called and they said the basement installation would not work in my case with water leaking up through the floor, and it would have to be installed in the front yard.

Here's a sketch to better explain what I was suggesting in my last post. My best guess of what my DWV system looks like is drawn in black. I don't know if the drain pipes go under the foundation as shown, or through the foundation/basement wall. The suggested changes are in red. If the drain pipe can be plugged where shown, I am not sure I would need the sump pump (see previous paragraph) or the external drain. The external drain in the diagram would just be a 4" vertical pipe down to a stone bed above the French drain. I would expand it to 8" or 12" at the bottom to increase the area of contact with the stone bed. The hole could be dug with an auger.

Is there a standard method to plug that pipe as shown without digging? Can water be leaking around it? I have never used that drain. Can I assume that nothing else ties into it from inside the house?

 

[frodo]

..................

 

[Mr_David]

Like I said before. Install a backflow valve but the problem is it's gonna be deep. DO NOT pump the water back into the ground and into the perimeter drain. You're just feeding the fire. You're probably right about being dry most of the time. if you have a high water table the perimeter drain is keeping you dry. But fails you when the storms hit. Pump the water onto the ground away from the house. If it's raining, it won't matter much.
If it's to deep to install a backflow valve then do like your neighbor and install a valve inside or a backflow valve inside. At least that will protect you from a full on holy mother of a flood backing up out of the floor drain if the main storm drain becomes completely blocked.
The addition of the sump will help keep you dry when the storm drain can't take away the water that is seeping up through the floor.

 

[Mr_David]

Never understood why someone would build a home with a basement in a swamp or on land that has a high water table.

 

[sburtchin]

Never understood why someone would build a home with a basement in a swamp or on land that has a high water table.

The short story - In the old days basements were essential to our farming community. We grew up with them and love our basements.

Most homes have sump pumps or 2 or 3 of them, which are a constant headache. I purposely bought a home near the top of a hill to avoid that. It was 17 years old at the time with no sign that any water had ever been in there. The first flood event was around 1988 with more rain than I am ever likely to see again in my lifetime or the next 50 years. I talked to people whose basement windows were pushed in from the water pressure. That should have been the last. What I didn't expect was that my local government would allow the drainage ditch that serviced my home to be dammed up and replaced with a pond.

 

[sburtchin]

Pump the water onto the ground away from the house. If it's raining, it won't matter much.

Well, that was what I considered first - to just pump the water onto the back yard as it flows in. The pump would need to have 100% duty cycle and enough capacity to keep up. If I could plug that pipe where shown in my sketch, there would be a lot less water coming in, or maybe none. My foundation should be sitting on what we call jackwax, so the only water coming in has to be through that pipe or around it and/or around the sewer pipe.

The addition of the sump will help keep you dry when the storm drain can't take away the water that is seeping up through the floor.

I think the water seeping up through the floor is because the floor drain pipe is either busted or otherwise leaking. The clay is so dense here, I cannot see any significant amount of water seeping in except through or around pipes. If I cut a hole in the floor, how deep do I have to dig to find the pipe? Is there a common practice - under/through the foundation?

Like I said, I never use that drain. My neighbor solved his problem with a valve and no sump pump. If I can plug it with concrete or expanding foam or rubber plug or whatever, that would be just as good as a valve as far as I'm concerned.

I can still add a sump pump for insurance. Looks like that valve by itself costs about as much as a whole DIY sump pump installation.