I am not sure of the correct terminology. But, every property that I have
ever seen or owned (in and near New Jersey) has had a sewer line vent at or
near the curb. Taking off the vent cover shows a vertical sewer stack that
goes down to the lateral sewer line that runs into the town's sewer system.
There is usually (or always?) a trap in the lateral sewer line between the
vertical vent pipe and the town's sewer line.
Here's one link that I was able to find that references the trap/vent at the
top of the second page of the document.
My old house has manhole cover over sewer line. It did have a hole in the
middle. It was in the neighbors yard across street. My line came into that
pit about two feet down, then sewer line several feet below. If pressure
built up to shoot out hole, then it would enter basement. I had drains
plugged, except for shower which needed to go over about six inches of
barrier. Pressure was high that day, enough to shoot over barrier, even
though my basement floor was below the manhole cover. It took me three
hours to get home that horrible night. Traffic was bad, everything flooded.
I even left work early. Had bad feeling when home phone would not ring.
That's called suburbia not city.
both have sewer lines that go straight down into the basement floor. The
basement is unfinished but I have plans to frame and start the finishing process
during the summer of 2013. This includes adding an additional full bath.
and spills across the basement floor. Most incidents are minor and may get 20%
of the basement floor wet, but once the entire basement had 2-3" of sewage and
it came from the floor drain and the cleanout in the main stack from the
upstairs bathroom. (cleanout is only 2" above the floor)
the same gravity feed system but with a pit to allow for use during backflow
issues. This involves a double backflow valve, T splitter to allow sewage from
house to spill into a pit when the valves shut, and an ejector pump to force the
sewage out in front of the valves when sewers are backed up.
main line from house would dump into the pit, an ejector pump would pump the
sewage 6ft vertically and then back down into the main line out of the house.
This creates a mock overhead system to prevent backflow from the city.
floor drain would sealed shut, main stack from second floor bathroom replaced
with PVC so that the cleanout is 2ft higher, and install an ejector pump for the
laundry tub and future bathroom.
I had similar problems in the old house in the southwestern suburbs of
Chicago. In my case, it happened maybe every 3 or 4 years. As the
sewer line under the basement floor was cast iron, I put a rubber
stopper in the one floor drain. However, I was awakened one morning at
3AM by the neighbor's phone call saying the sewers were backing up!
None came from the plugged floor drain. However, there were 2 other
drains; one in the laundry tub and one for the furnace (AC condensate,
recuperative furnace and humidifier). Both of these had check valves.
Check valves don't work when the water level rises slowly. So, it was
coming out of the drain by the furnace and the laundry tub was almost
full to the top. My wife then plugged the drain by the furnace. I
siphoned the water in the tub to the sump pit. As there was now a large
difference in pressure on the 2 sides of the check valve, it closed
tight. I then vacuumed the water on the floor.
I went to the town's public works director and ask him when this might
stop .... when the water gets up to the ceiling joists? He sent out one
of his guys who checked out the details and recommended back to his boss
that they put in a anti-backflow system. They contracted with a local
company called Safe House or something similar. The bill was about $5K
and was not paid by me. They installed a manhole in my front lawn with
a removable 20" square grass pan for access. The unit itself operated
via a float which would close the gate ... back pressure would then hold
it closed. If you continued to use the drains in your house, the sewage
would flow into an ejector pit at the bottom of the manhole and get
forced into the backing up sewers (probably into my neighbor's
basement). I never had a problem after that and I used it as a selling
point, when selling the house. The town had maybe a dozen houses that
were at the right (actually wrong) elevation, where this problem
occurred. Apparently, they fixed them all. You might try this.
Nice idea, however, as I said in my previous post, simple check valve
don't work when the water rises slowly. At 1st, there is no pressure on
either side of the flap. Then as the water from the sewer rises just a
little, there is always a little leakage, so it seeps through, evening
the pressure on each side. This continues until the water apparently
backs up, slowly. Maybe others have had success, however, my experience
is that you need a rapid rise in order to close the flap tight and fast.
As I posted above, there are others that use a float to close the
flap. As to the ejector, in my case, it was there only if you continued
to flush or run water down the drains, while the sewers were in a backup
condition and the flap is sealed closed. Drain water from the house
would push through another valve as pressure built up from the house
side, and this sewage would then go into the ejector pit and eventually
get pushed into the sewers by the ejector pump.
That backflow preventer will stop the city sewer
from flowing back into the house system and
coming out the floor drain in the basement floor
or the laundry sink, etc.
That solves the worst part of the problem, which
is unlimited sewage flowing into the basement.
But it doesn't solve it all.
Now, ask yourself what happens if the city sewer
is backing up, the backflow valve is activated
and you fush a toilet upstairs or take a shower?
I have no idea whether these thoughts might help you, but anyway ...
My backing up problems were because of an obstructed sewer line to the
street, plus the street sewer had backed up as well. A neighbor across
the street had backups as well, even after his lateral had been fixed.
So I asked the guy who did my lateral to take a look into the street
sewer. He also does work for the town, so it was easy for him to
convince the town that the street sewer needed fixing.
Once those were fixed several years ago, no more backups.
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