That is going to be tough to answer without having been to the site and more. They have the info and would know better than anyone on the internet.

Waste lines need to be pitched in order to function properly (if stuff is going to flow downhill driven by gravity, there needs to be at least a small hill.) The required pitch in our state's plumbing code is 1/4" per lineal foot for horizontal drains 2 1/2" or less in diameter, and 1/8" per lineal foot for horizontal drains 3" to 6" in diameter. The OP should check to ensure the work complies with whatever code is applicable in their area.

Fair. I am just wondering how common this level of fiasco is in home building.

"Has anyone heard of this?"

No, but it is completely believeable.

"Is there no easier way to repair it?"

Not that I can think of.

"And even if they pay for the fix, do we have any recourse for the giant mess they are about to make in our (finished) lower level?"

If you get them to do the repairs without a lawsuit, you're doing well. Tell them if they do and get inspection to approve, you'll eat the cost of the reassembly and cosmetics.

See if a mudjacker could pump out the belly.

@Joseph Corlett, LLC We have photos of the plumbing and sewer lines being laid before the concrete was poured in the basement floor. It's clear from the photos that the line has no pitch and the guys who were here acknowledged as much. It's not just a belly in one spot, -- there is standing water in the pipe from the toilet to the backwater valve, so they can't really say it isn't their fault...it's not like one spot has sunk with compacting soil. So I don't see why we should pay for any of this. Frankly, they looked a little sick to the stomach when they saw the situation.

That said, we have contacted a lawyer in case we need him.

Whatever they take apart, they have to put back in the finished condition it started in. The plumber may have to pay for another sub to do anything out of his area of expertise. Line all that up before the work begins. That's just logic. Your builder may be able to use the original guys who did the wotk 3 years ago. Everything should be spelled out as part of the complete job.

Before the drain installers backfill in our builds, the municipal inspector does a simple test--they drop a ball of paper and water equivalent to a w.c. flush and check that it comes out the other end purposefully. I'm always on hand for that one. Guess someone forgot to undertake such a "complicated" procedure for your home.

If it's a tract build, the builder will hold the drain installers liable--if they ever want another contract from them! Glad to hear your jurisdiction makes the responsibility for latent defect legislatively clear.

"If you get them to do the repairs without a lawsuit, you're doing well. Tell them if they do and get inspection to approve, you'll eat the cost of the reassembly and cosmetics. "

I disagree a bit:

Most warranties exclude "consequential damages" - but they are indeed getting off cheap if there aren't attorneys involved. I would be inclined to negotiate a flat fee for the reassembly and cosmetics. No contractor wants to sign a potentially blank check - but if you can say, $15k, or whatever is reasonable - and get talked down a little so they feel like they negotiated some. That's still cheaper than if the suits get involved, for everyone. It may not cover all your expenses, but it's something.

@dan1888 That is my expectation. Time will tell. We're waiting for the plumber to come back to us with what the repair will entail and what they are willing to do.

@worthy Seems like that should be basic construction/plumbing 101. This is in a tract development that is still building out, so I will be curious to see if any other neighbors have similar issues. I do know one home that was built in 2017-2018 has had plumbing problems, but not the same ones. Grrr.

basic construction/plumbing 101

About as basic as you can get: water runs downhill!

When licensed, we never built more than two infill houses at once, so there was a level of oversight tract builders don't provide. Used to be a ratio of one super per every 50 houses around here.

@worthy We thought we had a great construction manager, and my husband was on site pretty much daily calling out anything we saw that wasn't right. I guess we assumed too much in expecting the water to run downhill. 🤣

daily calling out anything we saw that wasn't right.

Like watching surgery on TV. You don't know what you don't know.

We had a client who dropped by most every morning. An errant drop of paint was a catastrophe. But an un-reinforced foundation corner. Uh? (Fortunately, we spotted and corrected it.)

Like watching surgery on TV. You don't know what you don't know.

Haha. So true. We weren't that picky, but we did catch some crazy things that needed to be caught.

My 2 cents… This is likely negligence and thus the disclaimer for consequential damages probably doesn’t apply.

I would be more concerned about contractors passing the buck. The plumbers should have known better but they can’t create a slope where one doesn’t exist. If the basement was poured with no slope to the sewer hookup then one isn’t going to magically appear. They certainly should have stopped work and notified the contractor but that is something the contractor would need to address. I would honestly talk to an attorney. You don’t have to sue anyone just to have a consult, but I suspect you could spread some of the cost around and get close to being made whole.

@bry911 We contacted the builder and their first response was to tell us our warranty had expired. If my husband hadn't done his research and found out our state has a six year period for latent defects, they would have just shut us down. Of course, their next step was to point fingers at the plumbers. I hope we don't need a lawyer, but we have one lined up.

It's also obvious (in retrospect) that the slope of the plumbing run (before the basement floor was poured) is not sloping much if at all.

The plumbers should have known better but they can’t create a slope where one doesn’t exist.

When I build, I check the sewer main line depth in advance. On one build, the municipality initially told me the line was only 7' deep. So I left a hole in the poured foundation wall, figuring the drains would run under the first floor and any basement drains would use a sewage pump. Turns out the line was an exceptional 12' below street level.

In our area, at least for new builds, drainage and plumbing contractors are separate specialities.

*****

This is like one of those minor repairs in a vehicle. But it's the getting to it and out that's the real work.

This is like one of those minor repairs in a vehicle. But it's the getting to it and out that's the real work.

That pretty much sums up the facial expressions of the plumbing and sewer guys. They spray painted the spots on the floor that need to be open and it's going to be a hot mess.