Backwater valve mistake by homebuilder

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KSdoit

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I believe I have discovered a major mistake by the homebuilder of my house and am seeking advice on how to proceed.

My unfinished basement floor is below the elevation of the manhole cover of the next upstream manhole. All my upper floors are above the elevation of the manhole cover of the next upstream manhole. And as I understand IPC 2018, all of my basement floor's plumbing fixtures (emphasis on all fixture) should be protected by a backwater valve, which would include the basement's floor drain as I understand it. And likewise, all my upper floors should NOT be protected by backwater valve. (IPC 2018 Section 714)

However, it appears the only pre-installed under slab backwater valve in my unfinished basement is only protecting the future bathroom group's pre-installed plumbing. The floor drain (which happens to be on the other side of the basement) is connected into the branch that services the first and second upper finished floors of the house and this branch connects downstream of the backwater valve. Therefore, this basement floor drain is not protected by the backwater valve.

My questions are, am I correct this floor drain should have been protected by a backwater valve and its current connection to an upper floor's underslab branch is breaking other codes including venting through a wet vent via the upper floor's drain stack?

If I am correct, what suggestion exists for fixing this? In IPC 2018, there is an exception that reads: "Exception: In existing buildings, fixtures above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not be prohibited from discharging through a backwater valve."

Since this is a single family residential home built in 1999 and this is a basement finish of an unfinished basement, would this "existing buildings" exception allow me to install a 2nd backwater valve (via breaking up the concrete and locating a spot to install a backwater valve on the branch currently servicing the floor drain and the upstair fixtures)?

This seems the only way I can think to protect the entire basement fixtures unless someone has another approach to this problem.

Thank you
 

KSdoit

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Unfortunately the 4 feet of branch from the floor drain to the main drain is sitting directly under the HVAC. A backflow valve would not work in that short portion of drain to solely protect the floor drain.
 

Reach4

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Is basement sewer backup common in your area? The most positive effective solution is to convert to "overhead sewers", where the basement waste gets pumped up to join the gravity-fed waste from the first floor and above. This is not an inexpensive solution. It will eliminate sewer backups into your basement.

Flapper type normally-closed valves normally leak. Maybe you are looking at the more-effective normally-open type valves.
 

KSdoit

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To rephrase and simplify my question: Should a basement floor drain be protected by a backwater valve IN ADDITION TO the basement bathroom group as per the 2018 IPC? If so, would it be proper building technique to make sure the underslap plumbing had a single properly installed backwater valve (i.e. accessible for maintenance, downstream from all these basement fixtures) that was protecting all these fixtures (both the basement bathroom group and the basement floor drain). I'd like some confirmation that the original installer made a mistake when they put the floor drain on the upstairs branch that is not protected.
 

Jeff H Young

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I belive the house was not built to code my code UPC hasent allowed what you built in my over 35 years in the trade. ill let you research your code in determining which code was in effect at the time of build and how the code was writen at the time.
I read code 714.1 I cant really make heads or tails with confidence. What a backward way to write a code!!

" Exception: In existing buildings, fixtures above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not be prohibited from discharging through a backwater valve".
So i guess that means if its not a new building you can go ahead and install a B/W valve even though upper floors discharge into it , after all "shall not be prohibited "is clear? I think you could argue entire house can be on a B/W valve kinda dumb but thats what it says, I cant even guess the intention with certainty
I think a discusion with the building department is in order also I thgink befor visiting with them you should decide how you would like to proceed and then seek thier blessing or at least know what you want to argue about or for ? what do you propose ?
 

Tuttles Revenge

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So to answer the question. Yes, all fixtures in the floor levels below the next upstream manhole cover should be protected by a BWV.

Some manufacturers make floor drains with ball floats in them that prevent back flow, so maybe not as much excavation.

We install backwater valves on many of our projects as remodels.. no exceptions for this rule since 2006. Its been in our UPC code forever, but until 2006 I had never installed a BWV.. nobody cared about them and most inspectors would have considered them as a flaw. Now they're super strict after several people were killed in their basements from flooding sewers.
 
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