Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.

Frank

On Friday, August 19, 2016 at 12:19:35 PM UTC-4, franks wrote:
Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.

Frank

A "sewer plug" is typically used to cap a clean-out. They look like this:

http://preparednessadvice.com/wp-con...12/sewer23.jpg

http://www.homedepot.com/catalog/pro...e1cdad_300.jpg

A "check valve" is used to allow fluids to flow in only one direction. They
look like this:

http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg

http://www2.lsuagcenter.com/domains/.../flapcheck.gif

They are 2 completely different animals designed for 2 completely
different purposes.

On Friday, August 19, 2016 at 12:39:27 PM UTC-4, DerbyDad03 wrote:
On Friday, August 19, 2016 at 12:19:35 PM UTC-4, franks wrote:
Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.

Frank

A "sewer plug" is typically used to cap a clean-out. They look like this:

http://preparednessadvice.com/wp-con...12/sewer23.jpg

http://www.homedepot.com/catalog/pro...e1cdad_300.jpg

A "check valve" is used to allow fluids to flow in only one direction. They
look like this:

http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg

http://www2.lsuagcenter.com/domains/.../flapcheck.gif

They are 2 completely different animals designed for 2 completely
different purposes.

I think what he means is will plugging the floor drain in his basement
that goes to the sewer stop sewage from backing up into the basement,
like a backflow valve would. The answer is yes, but it will only
stop if from coming out of that one drain, anywhere else, eg a drain
for a washing machine, would still be vulnerable. And IDK how you
put a sewer plug into a typical floor drain, the ones I've seen were
not designed to accept a plug. You might be able to get rubber
expansion type plug that would fit. I guess if you can do it and
that;s the only vulnerability, it will work.

It's not going to cause any pressure damage, there are plenty of
other places for the sewage to go.

Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.
Frank


A "sewer plug" is typically used to cap a clean-out. They look like this:
http://preparednessadvice.com/wp-con...12/sewer23.jpg
http://www.homedepot.com/catalog/pro...e1cdad_300.jpg
A "check valve" is used to allow fluids to flow in only one direction. They
look like this:
http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg
http://www2.lsuagcenter.com/domains/.../flapcheck.gif
They are 2 completely different animals designed for 2 completely
different purposes.



I think what he means is will plugging the floor drain in his basement
that goes to the sewer stop sewage from backing up into the basement,
like a backflow valve would. The answer is yes, but it will only
stop if from coming out of that one drain, anywhere else, eg a drain
for a washing machine, would still be vulnerable. And IDK how you
put a sewer plug into a typical floor drain, the ones I've seen were
not designed to accept a plug. You might be able to get rubber
expansion type plug that would fit. I guess if you can do it and
that;s the only vulnerability, it will work.
It's not going to cause any pressure damage, there are plenty of
other places for the sewage to go.


I have heard of basement floors heaving, from plugging the drains ..
Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

wrote in :

Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?

That's what my brother did in the basement of his first house. Basement floor wasn't much
more than 4 feet below grade, so he used about a 5-foot standpipe -- in any event, the top of
the standpipe was higher than ground level. Next door neighbor insisted that water was going
to come gushing out of the top of the standpipe and flood his basement anyway. My brother
said nope, not possible, ain't gonna happen. Of course he was right, and the neighbor learned
a little bit about science.

Naturally, this is dependent on making a watertight seal between the standpipe and the drain.
And before you ask... that was 15 years ago. I don't remember how he did that.

On Friday, August 19, 2016 at 1:50:14 PM UTC-4, wrote:
Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.
Frank


A "sewer plug" is typically used to cap a clean-out. They look like this:
http://preparednessadvice.com/wp-con...12/sewer23.jpg
http://www.homedepot.com/catalog/pro...e1cdad_300.jpg
A "check valve" is used to allow fluids to flow in only one direction. They
look like this:
http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg
http://www2.lsuagcenter.com/domains/.../flapcheck.gif
They are 2 completely different animals designed for 2 completely
different purposes.



I think what he means is will plugging the floor drain in his basement
that goes to the sewer stop sewage from backing up into the basement,
like a backflow valve would. The answer is yes, but it will only
stop if from coming out of that one drain, anywhere else, eg a drain
for a washing machine, would still be vulnerable. And IDK how you
put a sewer plug into a typical floor drain, the ones I've seen were
not designed to accept a plug. You might be able to get rubber
expansion type plug that would fit. I guess if you can do it and
that;s the only vulnerability, it will work.
It's not going to cause any pressure damage, there are plenty of
other places for the sewage to go.


I have heard of basement floors heaving, from plugging the drains ..
Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

Maybe from plugging drains designed to remove ground water, but not
from a floor drain connected to the sewer. For example, if you filled
in a sump pump pit with concrete, I can see that doing it. But no
way for a floor drain that's connected to the sewer.

On Fri, 19 Aug 2016 13:51:10 -0400, wrote:


Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.
Frank

A "sewer plug" is typically used to cap a clean-out. They look like this:
http://preparednessadvice.com/wp-con...12/sewer23.jpg
http://www.homedepot.com/catalog/pro...e1cdad_300.jpg
A "check valve" is used to allow fluids to flow in only one direction. They
look like this:
http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg
http://www2.lsuagcenter.com/domains/.../flapcheck.gif

The check valve I installed didn't look like either of these. It was
plastic like the second one, but didn't have a side-opening so I
couldn't see how the flapper was attached. I bring this up because I
put one in to prevent backups to my laundry sink, and to warn the OP
that, although our situations are different, it didn't work!^^^ Now
that might have been because lint from the washing machine^^ got in
the flapper hinge, but I hadn't had the valve installed more than 2 or
3 months, and I've taken a small step to keep lint out of the drain, a
plastic tube about 6 inches high that goes in the opening and has
small holes at the bottom, getting progressively bigger towards the
top, and then of course if there is more than 6 inches in the sink it
overflows the top of the tube. This does catch a lot of lint, and I
can't judge how much lint gets through.

^^(and yes I didn't put it in backwards or the laundry water would
have not drained or drained more slowly.)

^^My washing machine doesn't have a lint filter of its own, only a
lint chopper, that it said would make the lint small enough to go down
the drain, but that doesn't mean it's small enough to not mess up the
check-valve

They are 2 completely different animals designed for 2 completely
different purposes.

I think what he means is will plugging the floor drain in his basement
that goes to the sewer stop sewage from backing up into the basement,
like a backflow valve would.

Yes, that's exactly what he means.

The answer is yes, but it will only
stop if from coming out of that one drain, anywhere else, eg a drain
for a washing machine, would still be vulnerable.

True**, but in most cases those other drains will be higher than the
floor. I dont' have a floor drain myself*** and my lowest (other)
drain is the laundry sink, I'm guessing 24" higher than the floor. And
height is everything wrt water backing up into the basement.

**Assuming the drains are connected, which I think is the normal
situation, but then there is the example that hubops gives further
down.

***except the sump, for the sump pump, which water spilled on the
floor could drain into, except for the plastic lip around the sump. I
put holes in the lip so the water level on the floor wouldn't have to
be higher than the lip, but I haven't enough water on the floor since
then for water to even reach the sump, to see if I made the holes big
enough.

And IDK how you
put a sewer plug into a typical floor drain, the ones I've seen were
not designed to accept a plug. You might be able to get rubber
expansion type plug that would fit. I guess if you can do it and
that;s the only vulnerability, it will work.
It's not going to cause any pressure damage, there are plenty of
other places for the sewage to go.


I have heard of basement floors heaving, from plugging the drains ..

As I hinted above, I don't, or didn't, understand this. Was the
floor drain not connected to any other drain? I guess that's
possible, likely?, if it's only connected to the storm sewers and it's
the storm drains that are backing up. But the sinks (on any floor)
are connected to the sanitary sewers, so they're totally separate.

In my case, they would be separate, but the stream, which is our storm
"sewer" will rise high enough to overflow the sanitary sewer manholes,
fill the manhole with water and back up the sink.

It seems unlikely that the OP has my situation, but he should make
sure of that.

Rather than a plug - if you could seal a temporary standpipe - the

Temporary is another question. If this is caused by heavy rain,
people can't predict when the rain will be that heavy, or they may be
asleep or at work. And even when I'm home and awake and looking out
my window, when it's dark out, I can't really tell how heavy it's
raining or if, for example, my parking lot has started to flood. And
in my case, it's not totally the rain at the moment but the rain over
the previous day or several days, which raise the level of the stream
with time. We don't know the source of the water causing the OP's
backup, or if he can see it coming (when he's at home and not
sleeping, etc.). (If they're out of town, they could put in the
standpipe before every trip, but that won't help when they forget or
they're not out of town.) I have to keep my laundry sink plugged^^^^
all the time except when I'm using the washing machine, because I
can't be there to plug it up when it starts to rain. And during the
last big rainstorm (which made the national news when Ellicott City
flooded), all three of my vulnerable neighbors had flooded basements
even though they all knew about plugging their sinks.

So it would really have to be permanent, either a pipe sticking up in
the middle of the basement floor, easy to break when one knocks into
it, or maybe a pipe that bends, goes along the floor to the edge of
the room, and then straight up.

^^^^And by plugged, I mean a rubber plug with a one-by stuffed hard
between it and a shelf above it, a shelf with 40 pounds of weight on
it, plus it's firmly attached to the wall. When I just used the
rubber plug and a brick, a heavy brick fwiw, the water just pushed the
plug up anyhow. (In theory I can't use the washing machine when it
might flood, but I've never actually bumped into that situation. If I
did, I'd have to force the plug and the wood in place (at the same
time) even when the sink was full of water, which I think would be
possible.)

water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

On 8/19/2016 1:51 PM, wrote:

Will a sewer plug work the same as a Backwater Check Valves? And will
it cause water pressure damage to the sewer drain under the basement
floor if the drain system gets overloaded from a heavy rain fall.
Frank


A "sewer plug" is typically used to cap a clean-out. They look like this:
http://preparednessadvice.com/wp-con...12/sewer23.jpg
http://www.homedepot.com/catalog/pro...e1cdad_300.jpg
A "check valve" is used to allow fluids to flow in only one direction. They
look like this:
http://cdn.balkanplumbing.com/wp-con...ater-valve.jpg
http://www2.lsuagcenter.com/domains/.../flapcheck.gif
They are 2 completely different animals designed for 2 completely
different purposes.



I think what he means is will plugging the floor drain in his basement
that goes to the sewer stop sewage from backing up into the basement,
like a backflow valve would. The answer is yes, but it will only
stop if from coming out of that one drain, anywhere else, eg a drain
for a washing machine, would still be vulnerable. And IDK how you
put a sewer plug into a typical floor drain, the ones I've seen were
not designed to accept a plug. You might be able to get rubber
expansion type plug that would fit. I guess if you can do it and
that;s the only vulnerability, it will work.
It's not going to cause any pressure damage, there are plenty of
other places for the sewage to go.


I have heard of basement floors heaving, from plugging the drains ..
Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

A plug in the floor drain will stop backup water from entering the
basement, if the pipes below the floor are completely sealed, like cast
iron or plastic. Now, if the pipes are the old clay tile types, the
seal is usually only something like cement or mortar. When there is
back pressure, each joint will ooze and water will enter the gravel,
mud, clay under the floor. Eventually, the floor might try to float,
thus causing the previously mentioned heaving. In my previous house of
almost 40 years, the pipe was cast iron and the floor drain was plugged.
No problems. However, as the sewer system got more overloaded through
the years and more illegal gutter/sump pump connections, there were
other problems, the sink and the drain for the furnace/humidifier/AC. I
put a check valve on both. Unfortunately check valves don't work well
for slowly rising back pressure, so during a bad storm, the sink
actually filled within 3" of the top. I connected a siphon from the
sink to the sump pit to empty the sink and once the water level was down
in the sink, there was lots of back pressure to keep the check valve
tightly closed. I just put essentially a cork in the furnace drain
line, which stopped it. Later, I contacted the town's public works
director asking him why? He said there are many illegal hookups
(gutters, etc) and others where the storm water just leaks into the
sewer system, like the pick holes on the manhole covers. He said one
would be no problem, but for 100s of covers it can add up. BTW, they
were replacing the covers with leak proof designs. But I digress. The
town offered to put in an anti back flow system. It consisted of a
float operated check valve located in a manhole they installed in my
front yard. When the water rises in the device, a mechanical
parallelogram arm closes the valve. The backup water will continue to
hold the valve tightly closed. There was also an ejector pump that
would force sewage from my house into the (now backing up) sewer system
.... I suppose into a neighbor's house without this kind of system. BTW,
not trusting all of this, I kept the floor drain stopper in place and
also had a 2" ball value in the sink drain, plus another 1" ball valve
in the line coming from the furnace. The good news is that I never had
to close either of these.

On Sat, 20 Aug 2016 09:12:03 -0400, Art Todesco
wrote:

.....

I have heard of basement floors heaving, from plugging the drains ..
Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

A plug in the floor drain will stop backup water from entering the
basement, if the pipes below the floor are completely sealed, like cast
iron or plastic. Now, if the pipes are the old clay tile types, the
seal is usually only something like cement or mortar. When there is
back pressure, each joint will ooze and water will enter the gravel,
mud, clay under the floor. Eventually, the floor might try to float,
thus causing the previously mentioned heaving. In my previous house of
almost 40 years, the pipe was cast iron and the floor drain was plugged.
No problems. However, as the sewer system got more overloaded through
the years and more illegal gutter/sump pump connections, there were
other problems, the sink and the drain for the furnace/humidifier/AC. I
put a check valve on both. Unfortunately check valves don't work well
for slowly rising back pressure, so during a bad storm, the sink

Good ppoint. I hadn't thought of that.

actually filled within 3" of the top. I connected a siphon from the
sink to the sump pit to empty the sink and once the water level was down
in the sink,

As you illustrate, the back pressure was rising slowly, but as the
water in the sink got deeper, the anti-back pressure was rising too.

In my case, I think the maximum water height outside is 6 or 7 feet
from the floor of the basement, but it can be less. The bottom of the
sink is about 2 feet from the floor but the top of the sink is a
little over 3 feet. If the water outside my house is more than 3 1/2
feet above my basement floor, that extra foot isn't enough to keep the
water out, but it does negate a foot's worth of pressure, so that's
another reason the check valve still doesn't close.

there was lots of back pressure to keep the check valve
tightly closed. I just put essentially a cork in the furnace drain

This is the condensate, right?

line, which stopped it. Later, I contacted the town's public works
director asking him why? He said there are many illegal hookups
(gutters, etc) and others where the storm water just leaks into the
sewer system, like the pick holes on the manhole covers. He said one

In my case, the septic sewer was built around 1977 and the first sink
backup I had was about 1987, so I'm thinking there weren't many leaks
by that time. In addition, I don't think anyone had hooked their
gutters or sumppumps to the drain. It would be more difficult than
running the drain to the curb. Well, the guy two doors away didnt'
live as close to the street as 90% of the people here do, and he
didn't like tthe sump pump water shooting out onto the sidewalk
leading to the front door, so he did route it to the house drain. He
was able to sell his house that way, and I think I pointed out to the
new owner that when the sink was backing up, pumping the sump water
into the same drain would just get more water on the floor. But he
or she didn't do anything until they wanted to sell the house and that
time the buyer had a house inspection, and it made the seller route
the sump as it had been originally.

But the pick holes (never heard a name for them before) are definitely
a major problem, and I would think the circumference of the manholes
aren't perfect either.

I too called the county, and he was the one who suggested waterproof
manhole covers -- I had never heard of such a thing -- but he also
said they wouldntt' help. Since he was still willing to put 2 of them
in, I saw no reason not to believe him. But I gave him two
locations, the manhole only 30 feet from my yard and ... I couldn't
figure out which would be more important, the next manhole downstream,
or the one upstream, and I don't know what I said. And for that
matter, I'm not sure he did it, buit I plainly couldnt' rely on it
anyhow, so I pursued other remedies.

would be no problem, but for 100s of covers it can add up. BTW, they

In my case, I'm pretty sure the water isn't higher than many of the
manholes. After all, they were designed to be higher than the water.
The one nearest me sticks up 8 feet from the ground. The stream only
goes another 5 or 6 miles upstream and the valley the stream empties
is no more than 1/2 mile across, maybe less, so surely the upstream
half of the 5 miles doesn't overflow. (Though they built a new road
about 3 miles upstream with a bridge over the stream, and the bridge
is higher than one who didn't know about the flooding would expect.).

were replacing the covers with leak proof designs. But I digress. The
town offered to put in an anti back flow system. It consisted of a
float operated check valve located in a manhole they installed in my
front yard. When the water rises in the device, a mechanical
parallelogram arm closes the valve. The backup water will continue to
hold the valve tightly closed.

So how long does it usually stay closed?

There was also an ejector pump that
would force sewage from my house into the (now backing up) sewer system

Wow. Are you the only ouse which faced a wet basement? Do your
neighbors know all that the town did for you? Don't they want it too?
I'm not sure I want this but it would have to work for 4 houese all
side-by side. One check valve would work if they rerouted 3 drains,
but I think they would need 4 ejector pumps. Maybe he was afraid I
would ask for all of that so he offered the waterproof manhole covers.
... I suppose into a neighbor's house without this kind of system.
BTW,

Hmmm.

not trusting all of this, I kept the floor drain stopper in place and
also had a 2" ball value in the sink drain, plus another 1" ball valve
in the line coming from the furnace. The good news is that I never had
to close either of these.

How does that work? The odds are 2 out of 3 that on a weekday you'll
be at work or sleeping when it floods. How are you going to close the
valves if you're not there? What about vacations?

On 8/20/2016 9:01 PM, Micky wrote:
On Sat, 20 Aug 2016 09:12:03 -0400, Art Todesco
wrote:

.....

I have heard of basement floors heaving, from plugging the drains ..
Rather than a plug - if you could seal a temporary standpipe - the
water would just rise in the standpipe to a level slightly higher than
the floor ... maybe ?
John T.

A plug in the floor drain will stop backup water from entering the
basement, if the pipes below the floor are completely sealed, like cast
iron or plastic. Now, if the pipes are the old clay tile types, the
seal is usually only something like cement or mortar. When there is
back pressure, each joint will ooze and water will enter the gravel,
mud, clay under the floor. Eventually, the floor might try to float,
thus causing the previously mentioned heaving. In my previous house of
almost 40 years, the pipe was cast iron and the floor drain was plugged.
No problems. However, as the sewer system got more overloaded through
the years and more illegal gutter/sump pump connections, there were
other problems, the sink and the drain for the furnace/humidifier/AC. I
put a check valve on both. Unfortunately check valves don't work well
for slowly rising back pressure, so during a bad storm, the sink

Good ppoint. I hadn't thought of that.

actually filled within 3" of the top. I connected a siphon from the
sink to the sump pit to empty the sink and once the water level was down
in the sink,

As you illustrate, the back pressure was rising slowly, but as the
water in the sink got deeper, the anti-back pressure was rising too.

In my case, I think the maximum water height outside is 6 or 7 feet
from the floor of the basement, but it can be less. The bottom of the
sink is about 2 feet from the floor but the top of the sink is a
little over 3 feet. If the water outside my house is more than 3 1/2
feet above my basement floor, that extra foot isn't enough to keep the
water out, but it does negate a foot's worth of pressure, so that's
another reason the check valve still doesn't close.

there was lots of back pressure to keep the check valve
tightly closed. I just put essentially a cork in the furnace drain

This is the condensate, right?
Yes, condensate from the high efficiency furnace and from the AC. There
was also a drain from the humidifier (AprilAire). That was on the non
sink line. There was another to the sink.


line, which stopped it. Later, I contacted the town's public works
director asking him why? He said there are many illegal hookups
(gutters, etc) and others where the storm water just leaks into the
sewer system, like the pick holes on the manhole covers. He said one

In my case, the septic sewer was built around 1977 and the first sink
backup I had was about 1987, so I'm thinking there weren't many leaks
by that time. In addition, I don't think anyone had hooked their
gutters or sumppumps to the drain. It would be more difficult than
running the drain to the curb. Well, the guy two doors away didnt'
live as close to the street as 90% of the people here do, and he
didn't like tthe sump pump water shooting out onto the sidewalk
leading to the front door, so he did route it to the house drain. He
was able to sell his house that way, and I think I pointed out to the
new owner that when the sink was backing up, pumping the sump water
into the same drain would just get more water on the floor. But he
or she didn't do anything until they wanted to sell the house and that
time the buyer had a house inspection, and it made the seller route
the sump as it had been originally.

But the pick holes (never heard a name for them before) are definitely
a major problem, and I would think the circumference of the manholes
aren't perfect either.

I too called the county, and he was the one who suggested waterproof
manhole covers -- I had never heard of such a thing -- but he also
said they wouldntt' help. Since he was still willing to put 2 of them
in, I saw no reason not to believe him. But I gave him two
locations, the manhole only 30 feet from my yard and ... I couldn't
figure out which would be more important, the next manhole downstream,
or the one upstream, and I don't know what I said. And for that
matter, I'm not sure he did it, buit I plainly couldnt' rely on it
anyhow, so I pursued other remedies.

would be no problem, but for 100s of covers it can add up. BTW, they

In my case, I'm pretty sure the water isn't higher than many of the
manholes. After all, they were designed to be higher than the water.
The one nearest me sticks up 8 feet from the ground. The stream only
goes another 5 or 6 miles upstream and the valley the stream empties
is no more than 1/2 mile across, maybe less, so surely the upstream
half of the 5 miles doesn't overflow. (Though they built a new road
about 3 miles upstream with a bridge over the stream, and the bridge
is higher than one who didn't know about the flooding would expect.).

were replacing the covers with leak proof designs. But I digress. The
town offered to put in an anti back flow system. It consisted of a
float operated check valve located in a manhole they installed in my
front yard. When the water rises in the device, a mechanical
parallelogram arm closes the valve. The backup water will continue to
hold the valve tightly closed.

So how long does it usually stay closed?

Don't really know, however, it should open when the backup stops. I've
seen it stop backing up usually right after the rain stops.

There was also an ejector pump that
would force sewage from my house into the (now backing up) sewer system

Wow. Are you the only ouse which faced a wet basement? Do your
neighbors know all that the town did for you? Don't they want it too?
I'm not sure I want this but it would have to work for 4 houese all
side-by side. One check valve would work if they rerouted 3 drains,
but I think they would need 4 ejector pumps. Maybe he was afraid I
would ask for all of that so he offered the waterproof manhole covers.
... I suppose into a neighbor's house without this kind of system.
BTW,

The only house near me with a deep enough basement, was immediately next
door. Of course he knew that the town did this for me. He just didn't
complain to the right people, or anyone, for all I know. When talking
the the public works director, he said there were about 30 or so houses
that had problems and were remedied with this system. I guess the
squeaky wheel gets oiled. Also, things now are different as the sewer
system has been taken over by private company. I'm glad I jumped in
when I did. But I really don't care at this point because I sold the
house 7 years ago. BTW, I saw the invoice for the anti back flow system
and it was around $5K.

Hmmm.

not trusting all of this, I kept the floor drain stopper in place and
also had a 2" ball value in the sink drain, plus another 1" ball valve
in the line coming from the furnace. The good news is that I never had
to close either of these.

How does that work? The odds are 2 out of 3 that on a weekday you'll
be at work or sleeping when it floods. How are you going to close the
valves if you're not there? What about vacations?

Well, I did this before the anti backup system was installed ... just in
case. This was an exceptional rain. A friend withing a mile from me,
measured 23" over 36 hours. At a mile away, my results may have been
lower or even higher.