Sewage Backflow Prevention

It seems to me you are disregarding the larger problem of the line becoming blocked in the first place...I would first find the cause of the problem and correct that....Usually it's a young teen girl flushing sanitary napkins...it's a phase....otherwise you may have roots in the drain line, or the line itself needs to be replaced....as the guy that gets the sheit end of the stick here, it is up to you to correct this problem, nobody else cares...

I think I might consider draining the washer into a sump and pumping that into the drain...and putting a check valve on that....second it occurs to me that you might just be moving the problem to the next lowest drain position, which is where?

Start at 2:30...

A macerating pump might be useful.

Actually I know the cause of the blockage this time. The drain cleaners pulled out a big wad of baby wipes, or more likely the sanitizer wipes that have become popular in the past year. Someone in this block has been flushing these down their toilet. In the past, the problems were traced to the connection with our line with the city's line. This was corrected, and I have not any problem until now for the past two years.

Now that I think about it, my proposed "solution" could lead to even bigger problems. The sewage would just back up to the next lowest exit. This could be my first floor bathroom.

You don't think your neighbor's basement is lower than your first floor bathroom? My guess is it would go there first. You might want to give them a heads-up if you decide to install a check valve.

From what you're saying it doesn't sound like there are floor drains?

I'm curious as to how you know where all the 90's are unless they are exposed or on a floor plan/print?

Is this a suspended system that's running very close to the ground to allow for basement washing machines?

More information?

As for putting in a shut off / ball valve.

You would be the only one that would have water flow into their unit if you forgot to open it. Either way it's far better than having the sewage.

Of course like solar Eagle mentioned you are only moving the problem to the next opening in the system.

I would put it in a valve while being an advocate for the correction of the problem.

Considering it would be rather perminent. I might figure out how much an actuated valve cost and then add leads and components to detect the discharge water to open the system when the washer is draining.

The parts available in a couple of days ...and the price.. is astonishing.

3 nineties after the last input!!!???

My idea was a floating ball valve, like in a wet vac, The ball would rise up with the water level sealing the vertical pipe but the flow from the washing machine would keep it open when the pipe was empty.

As I replied to SE this would just move the problem to the next highest opening.

Perhaps, this could be coupled to some kind of alarm.

Yeah, then you would be alerted that the show was about to begin.

Maybe I missed it... is this a newly manifested issue, or been ongoing?
Is the invert elevation of the sewer tap known or knowable?

Hi,

Proprietary slam valves are available for sewage lines; google non-return valves and sewer. You would need to have an inspection chamber constructed in the ground down to the sewer downstream of the property you are protecting, cut the pipe and insert the valve.

I had one replaced in a public swimming pool a couple of years ago where the plant room in the basement was lower than the sewer line in the road (when people tell me 'they don't build things the way they used to' I cheer uncontrollably). It isn't a job for a DIYer and the valve does need maintained periodically since by it's very nature, it attracts non-PPP materials in the sewage but it will do the job.

The build up of sewage when it operates will be in the municipal sewer which will have much more capacity than the line through your home and should have some form of overflow. As to it meeting your building codes, I cannot say; it is a common sense solution but that is sometimes a commodity in short supply when regulations are being drafted.

The 4 inch drain line is exposed on the inside of the foundation walls about 3 ft above the floor level. Each unit is staggered, front to back by about 4 feet. this requires two 90º elbows between each unit. Each unit's stack enters the line from the top via a sanitary T. The washing machine drain pipe extends about 24" above the drain line.

The line connects to the city's system approximately 12" below where it exits my unit. I know this because the connection was excavated two years ago to correct a connection problem.

You certainly should be complaining about a plumbing plan that was not sized adequately, or configured appropriately, for starters...

You have an obvious health hazard every time your basement is thusly flooded...(has the (City/County/Other) been notified?)

Corrective re-construction is strenuously suggested, even if the main sewage line (out in the street?) is where the most frequent actual blockage starts...

Original Plan Checking tends to only tell if something is against the applicable Code(s), but not how to do a very good job of working effectively...

See my reply to SE.

I am on the board of governors of this condo association and we are well aware of this ongoing problem. Unfortunately, to correct the initial design problem would cost $$$$ which the residents here would not likely be willing to pay. This is not the city's problem. Their responsibility ends width our connection to their sewer system.

Since the clogs are happening after your unit. Would it be feasible to replace the last section with 6" drainpipe?

It's to bed it wasn't done at the last excavation.

In Chicago just about everything dumps into 6" pipes before going to the main.

Four Inch and 9 units sounds woefully inadequate.

OK, then, when is the next Governors' meeting?...

..."Sanitary wipes aren’t so sanitary when they clog sewer systems or create nightmarish “fatbergs,” heavy accumulations of grease mixed with undissolvable wipes that create blockages in sewer pipes and wastewater treatment plants.

The Philadelphia Water Department says workers are seeing a surge of these so-called “flushable” wipes clogging up the sewer system since the COVID-19 emergency — and it’s pleading with residents to stop tossing them down the toilet.

“We understand people want to be safe and are using more wipes these days, but flushing any wipe or any material other than toilet paper is just irresponsible,” Philadelphia Water Department Commissioner Randy E. Hayman said in a release."...

https://whyy.org/articles/sanitary-wipes-down-the-drain-bring-philly-water-dept-and-aqua-pa-pain/#:~:text=Sanitary%20wipes%20aren't%20so,pipes%20and%20wastewater%20treatment%20plants.

Exactly! Maybe, if I could find out who has been doing this, I could give the a dose of the virus.

Just buy a bunch of those stickers and have everybody place them on the toilets...that way everybody will know...

The objective is to prevent recurrence of the problem, i.e. the blockage.

• The residents' assembly is one place where prevention may be invoked.
• Installing a macerator on the main line is another.

A valve on a sewage line is a Bad Idea. The only correct place for one is at the municipal waste water works for isolating sections of the plant.

Have you considered a Hepvo valve?

Brave Sir Robin has identified the correct valve to install. It is required by the international code series to protect all devices whose "flood rim" is lower than the next upstream manhole on the sewer system you connect into. Its normal purpose is to prevent backups originating in the sewer system from flooding the low levels in a nearby structure. For example, see the International Residential Code (IRC) section P3008.

In this case, its application for your washer drain would probably be OK, and certainly prevent future problems.

--JMM

A costly and maybe not feasible solution, yet it is foul proof and take you out of the disadvantaged location, is to try to disconnect your place from the common line and have a new wye connection at the main line before the city sewer connection with a decent Back Flow preventer. This will transfer your problem to the next lower unit if the origin of the problem is not resolved.

Sounds like your code over there is VERY different from here in Aus. Each property is expected to have an "overflow relief gully" that is an opening (outside the building) slightly above ground level and below EVERY internal fitting so that any blockage overflows onto the ground as opposed to inside the premises.

Maybe a simple "T" connection to an outside overflow would at least eliminate the overflow from inside your premises.

If the problem is consistent and persistent, then maybe "routine maintenance" for the block needs to include flushing of the offending section of the drainage line at a frequency that is earlier than the blockage frequency.

Even if the identified debris is "flushable wipes" there is still a problem with the line that is catching these and allowing the build-up. Rarely, but possible, it could be that the fall in the line is too steep, allowing the water to flow away and leave the solids behind where they dry and stick to the walls, accumulating to eventually block the system.

I have seen some "backflow prevention valves" for sewerage systems, but they were mostly used to prevent stormwater backflow from the mains into private dwellings and were of questionable reliability when only needing to work once in a decade.

now you have 9 units,...

I’ll put this out there.

I had a Somewhat similar issue at work...

had some issues with our lab at work where their can having blockage issues. It had to pump waste up 26 feet and 300 + feet to the municipal sewer.

I found a macerator pump from Grainger Supply, where it solved this problem...

now since you have 9 units in your line,... Instead of having (9) macerator pumps maybe if one is installed halfway (of course it would need a receiving tank. This may take care of your problems...

otherwise you’d need a pump at each entry point. That would solve your problems.

and don’t forget to install a check valve.

Here is an article from a firm in Florida that seems to know a little. I doubt they are familiar with Massachusetts plumbing. The gizmo they show looks like it will handle solids well. Transparent has some advantages, too.

Getting in touch with a reputable, local provider is probably your best bet.

The Seattle waterfront area went through something a few years ago referred to as the "sewer wars" where sewage was backing up from toilets. The various businesses becan relocating restrooms to upper levels and finally resulted in some shops adding restrooms in additions on their roofs. The "wars" ended when the city finally fixed the sewer system in the waterfront area.

As was mentioned by others, there are backflow preventer valves that work reasonably well, but the best solution is to get the blockage identified and track down the source.

Otherwise install a standpipe with vacuum breaker and sewage pump and have your sewer entry point at a higher elevation than your neighbors. Suboptimal solution, but effective if you want to take the "Not in my basement" approach.

The Third Battle of Bull Run

I lived in a shiny, brand new condominium complex in Manassas, VA in the early 1970s. I also was a member of the BOG. We also had common sewer lines with crazy numbers of sharp turns under the last apartment just before the line entered the city system. As the pipes age, they erode and progressively snag more hair, wipes, sanitary napkins, grease and whatnot. We had several "special assessments" to get drain clearing contractors to clear stoppages. Each time the contractors would insert snakes and cameras and other equipment into the line. Each time the corners of the sharp turns developed more gouges, scrapes, and hangs which would then catch more hair,... About at the second special assessment we asked the contractor if the line met code and he laughed loudly and told us the many ways that it did not. We looked into suing the original builder and found out that builders do this often and the ones who do plan to go out of business under the original name and start a new business under a new name. After that shuck and jive it becomes extremely difficult to win a lawsuit even when the people are the same and only the names have changed to protect the guilty. We gave up on suing, had one last monster special assessment, took the last unit out of use for the period of busting up the slab concrete and replacing the common line with a larger diameter, smoother turning one with a terrific cleanout port just outside and tried to forget that our fellow man had been so inconsiderate. Later we also had a problem with de-lamination of the exterior wood sheathing. The large national sheathing manufacturer made good on the materials but the labor was enormous and lead to another monster special assessment. I am now no fan of properties with commons and I always look at how long a builder has been operating under their current business name. Luckily, Manassas was appreciating and I figure that by the time I left, much of the running total of special assessments had been partially offset by that appreciation so I only lost a few thousand per year off of my purchase price after living there a while. I try not to think about how much better off I would have been with an ethical builder.

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thewildotter

Are there any?

Get in, make a buck, and get out.

I live in a Ryland home built in '73 in the Annapolis area. They look pretty on the surface when new, but 30 or 40 years later when problems start cropping up, you don't have the scratch the surface very hard to find all the shoddy workmanship and penny-pinching shortcuts they took on materials and construction methods. I would NEVER buy a Ryland home ever again.

For instance, premium Corian® countertops on cabinets with 1/2 inch thick particle board shelves with the lousiest possible drawer slides.

How about 2 x 8 floor joists with a 13-ft. span? It might have met code at the time, but with kids in the house, trampoline immediately comes to mind as you watch your bookcases and china cabinets sway to and fro as they walk, let alone run through the house.

How about 3/8 plywood roof sheathing on trusses with 24 inch centers? 'Nuff said.

How about Homosote® for facia, soffits, and eaves? While that material may be suitable for some applications, it has almost no strength since it is essentially paper maché.

How about 3/8 sheetrock for the walls? Ceilings? -- O.K. Walls? NO!!

2 x 3 interior walls? You can't install a decent size electrical box in them. Ugh.

R-7 insulation in the exterior walls?

How about the thinnest Type M copper pipe? Yup, all my hot water copper lines have to be replaced because of pin-hole leaks. And yes, I am on municipal water, which is VERY good well water in this part of Anne Arundel County. I drink it straight out of the tap.

Standard wallboard behind the shower and tub surfaces. Not greenboard or cement board. Jeeze-oh-pete

How about copper-clad aluminum wiring? Gee, that 100% copper wiring costs more. Your 12 AWG circuit is only good for 15 amps. Uckers-fay. At least it wasn't solid aluminum. Although maybe that would have been better? The house could have burned down and it could have been rebuilt the proper way.

Essentially, a Ryland home is a consumable item that you will replace in its entirety one board, pipe, and wire at a time. <sigh>

When I think about why we bought this house in the first place back in '96 . . . . .

location

location

location. The only thing you can't change with most houses. Tiny homes excepted.

location, location, location p,... huh?...

They say when buying a home,... you buy the worse broken down home in the best neighborhood...

You’ve just convinced me not to,

All depends on how much sweat equity you like to put into a house. If you're paying somebody to do it, it's a much longer road to break even. Flippers are just "re-builders" with probably even less ethics than the original. There might be some good ones out there, but I wouldn't hold my breath waiting to find one.

New improvements would always scare me. If the current owner didn't "live" with it for a good while, who knows what you'll get.

How right you are, Brave Sir Robin !

You-betcha sweat equity matters. When I first moved in to this center unit condominium I added a really big pull down attic access because I could barely squeeze myself through the existing really-tiny hatch in a small-to-start-with closet. After being appalled at what I found in the attic for insulation and with the no longer absurdly poor attic access, I added some plywood attic walkways and did quite an upgrade(totally DIY for a very small amount of money) to the insulation situation. At the beginning of the first winter as a board of governors member I heard everyone else's summer HVAC bill sob stories. I would casually mention that I had upgraded my attic access so I could get more insulation up there and everyone else seemed put off by the idea of having to put in an adequate access to their attics.

One morning, after a hard frost, my adjoining neighbors and I were all going out our front doors to go to work. My BFF next-door neighbor turned around and then asked me, "Why is your unit the only one with a white roof ?" I answered, "Its because I put a big pull-down stair access to my attic and it is also why I never have to run my air conditioner and I have yet to turn on my heater this year." The word was then out. I was no longer ignored. One by one we were able to watch individual units' shingles turn white on frosty mornings. One of my neighbors started an un-bonded, un-licensed, un-official lucrative small business adding really big, easy access holes to his neighbors homes and installing insulation through those holes into the poorly insulated attics at a reasonable price.

I had left this story out before because it was a success story despite the builder behavior. Adequate attic insulation was, luckily, one of the things one could do on an individual homeowner's sole initiative. The boosted attic insulation on these two story units made an enormous difference. The sewage and sheathing were basically locked in to requiring bonded contractor types and huge markups because they involved the "commons." I always suspected that somehow the lawyers writing the deeds, the slam-bam-thank-you-mam builders, and the monstrously high commons maintenance costs in the area were all something more than merely predation by accident.

____________

thewildotter

Too many coincidences to be accidental. But sadly, too many people don't have your perception and think all this stuff is "just the way it is" and hardly give it a second thought.

It’s just like remodeling... For an owner to remodel a house A and to stick with the remodeling plan, if the remodeling is $60,000, expect to pay $100,000 to $120,000. Just from the surprises... Moreno on the upper end for the final costs.

Over this side of the pond most washing M?C outlets are like this

So all you would need to do to move the problem to the "next" place is to ensure that the point where the drain hose enters the standpipe is higher than the "next" place. I would make it a few inches higher and also modify the trap so that the output of the trap is higher than the "next" point, and. there is a long drop from the output of the trap to the waste pipe. That way the sewage can't get into the trap.