You need new cabinets.

Why do you think new countertops too?

@PPF. thank you for your feedback.

Perhaps I assumed incorrectly but the countertops have already been installed so I wasn’t sure if they could safely remove the counters without damaging it. That would be great if I didn’t have to pick out another slab.

I think it's borderline.

It's not really clear what happened here. It looks like there was a water leak and they replaced the bottom of the cabinet. There doesn't appear to be much water damage on the bottom of the cabinet but there is on the sides.

If something else happened - let me know.

If the plywood has swollen, become delaminated, or the joints coming apart, then a replacement is called for. If it's just discoloration, I would wipe it down with bleach solution, put a small fan on it, and call it good. The black stuff is mold - but that's pretty easy to fix.

These look like custom made cabinets. This won't be the last time there's water under there. You might consider some type of sealant in the area under the sink so water isn't absorbed into the wood so easily.

You can argue that it's new and should be perfect once... for me, I'd rather have them wipe it down with bleach, caulk the corners with silicone, and seal the interior so future water doesn't do as much damage.

@Jake The Wonderdog thank you for your feedback.

They actually aren’t sure what caused the water damage but because it hasn’t leaked in a week, they speculate it was just from residual water when everything was being installed. Who knows.

I agree with you that it is perplexing that most of the damage was to the back panel (the bottom panel was actually not replaced).

While there is a part of me that is frustrated that my brand new custom cabinets are damaged, I am also completely ok with just wiping down with bleach and covering with sealer if that is adequate.

I just wasn‘t sure if the damage was serious enough to warrant the time and energy to fit for new cabinets (this would be absolute last resort only if the cabinets were truly damaged).

To me, the answer to, "Is this damaged" is if the plywood is wavy, has become delaminated or the joints are coming apart. If not, it's structurally ok.

Again, that black stuff is mold - but people freak out about mold waaay too much. Nonetheless, bleach solution will take care of that. Just wipe it down and not soak it too much. Then dry it out.

I'm not clear though if this is under the sink - and caused by an identified plumbing issue. Or if this is near the sink - and a root cause isn't identified. If a root cause isn't identified THAT'S what would concern me. This has gotten significantly wet and stayed wet. That's not a little water that happened at install. If this is under the sink, the leak was identified and fixed, then clean it up and seal it. If this isn't right under the sink you have a problem and don't pay them until the source of the problem is identified.

Given that the bottom was not replaced, I'm more concerned that there is water on the outside of the cabinet - not something happening inside. This might be a leak around the perimeter of the sink, for example.

If these photos are two separate base cabinets, then you probably have to pull them. If that's the case, It's gotten significantly wet somehow and you need to understand how - and do mold remediation behind the cabinets.

Is this the sink cabinet and the trash cabinet?

Do you have a basement or crawl space to see what is happening under the cabinets and sub-floor?

@chispa you are correct that this is under the sink cabinet and the photo with the metal racks are for the adjacent trash pull out cabinet.

Fortunately i do have a crawl space so maybe I will go under and take a better look. Thank you for the suggestion!

@Jake The Wonderdog thank you again for your detailed thoughts.

I agree with you that not all mold is as terrifying as it seems but unknown water damage is frightening. I’ve called out a mold specialist to come out tomorrow to see if they suspect further water damage behind the walls — but should I be calling a plumber instead? I’m just at a loss as to what neutral third party is the correct professional to contact to help figure out what’s happening here.

And thank you for the suggestions on what to look for in terms of damage to the wood/cabinet box. I will take a closer look later this afternoon!

Question: can individual base cabinets be removed without taking out the countertops? That would be ideal!

" They actually aren’t sure what caused the water damage but because it hasn’t leaked in a week, they speculate it was just from residual water when everything was being installed. "

So they still haven't found the leak. And this isn't the result of "residual water" - this is some standing water that soaked into the cabinet boxes. If it WAS residual water, it would have been a puddle and they sure as heck should have resolved that before installing stuff.

@User who would be able to definitively tell me what caused the leak? Is it a mold remediation specialist (who I have scheduled to come out tomorrow)? Should I also be calling s plumber?

I will ask my contractor again but I think I’d like a neutral third party to help me just because I’ve been told on multiple occasions that they weren’t concerned about the water leak

Judging from the pattern of the discoloration, your cabinet either sat in a puddle prior to installation or there was a leak under it after installation. Water wicked up the cabinet sides and back. It doesn't appear like the plywood is coming apart, so I think you can remedy the issue by drying out the cabinet and installing 1/4" plywood "skins" on the interior of both sides and the back.

You are saying the contractor says there must have been a leak, but that it hasn't leaked in a week, yet they have not identified the cause of the leak. They need to put some effort into this.

Leaks don't just "go away" on their own.

I saw this in decade old cabinets the other day. In new construction it's unacceptable.

@User@Michelle misses Sophie @Joseph Corlett, LLC Thank you for your feedback. It helps empower me to be more vocal about finding the root cause since unanimous consensus seems to be that this is not just a small leak that happens during typical installation.

I have a mold remediation specialist stopping by the house tomorrow and I'll wait to hear their thoughts. I was unable to find any water damage in the crawl space but that's either a good sign (or a sign that I have no idea what I'm looking for, ha!).

Will I need to insist that my contractor/plumber remove the base cabinets to determine the source of the leak? Or is there a less invasive/destructive way to identify what caused the water damage? :) Since they have been dismissive of my concerns (in a non-malicious way, they really are nice people), I just want to make sure I know exactly how far to push this.

THANK YOU EVERYONE FOR SHARING YOUR OPINIONS AND EXPERTISE WITH ME!

https://www.servicemasterrestore.com/blog/mold-damage/mold-myths-will-vinegar-kill-mold

***Vinegar; NOT bleach***

"Question: can individual base cabinets be removed without taking out the countertops?"

It's possible, but a pain.

This damage appears to be from a little leak over a long time. Something like a loose faucet escutcheon that allows water to drip.

Where did these cabinets sit before installation? Like in your garage? could they have gotten wet there?

***UPDATE:*** The mold remediation specialist/home inspector confirmed that there is moisture in the cabinets and believes there is also likely mold (tests to be confirmed next week).

My question now is, what are REASONABLE and acceptable solutions to determine the source of water?

1. Cut out a piece of the plywood at the back of the cabinet? If yes, is this patchable?

2. Remove the toekick to see if there is any water damage beneath the cabinets?

3. Replace all base cabinets and potentially the countertops (which have all been installed)?

@weedmeister The cabinets were inside the home (in the living room next to the kitchen while the kitchen was being remodelled). I don't think it was installed wet but it's hard to say. =\

The thing is, and this is peculiar, it looks like the box was sitting in water rather than a drip. A faucet drip would show as trailing down the back wall, or as a center drip spot on the cabinet floor. Sitting in a puddle at the cabinet makers shop would likely involve other cabinets. Have you taken a flashlight and thoroughly inspected all of the other cabinets in the home? Be sure that this one is the only one, and you just aren’t looking at the other es, because that’s a sink cabinet, and (of course) you expect water issues there.

@User yes, the inspector was very perplexed by this water damage. He said it was odd that it didn't have a trail from above, or water damage to the floor of the cabinets, so the inspector just kept repeating how this was very bizarre.

I think that's a very helpful suggestion to look at all the other cabinets (I didn't put much effort to look behind the pull-outs or remove the protective covering to open the cabinets) but now that you and a few other posters commented that the cabinets may have been sitting in a puddle, I'll be more thorough in inspecting all of them!

I don't think a diagnosis that the cabinet sides and back (which are vertically-oriented veneers) wicked up moisture either from sitting in a puddle or a leak at floor level rises to the level of rocket science (I acknowledge my view that most home inspectors and "mold remediation experts" are idiots.) The cabinet bottom (horizontally-oriented veneers) would not be similarly effected if the cabinets sat in a puddle or wicked moisture from below.

It is important to ensure that if there was a leak, that it has been repaired. Drilling a couple of holes in the toe kick would allow for visual inspection utilizing a fiber optic camera. Such cameras are modestly priced and should be in every plumber's and remodeler's tool kit. After inspection, the toe kick can be covered with a 1/4" veneer "skin."

Provided the leak has been repaired and the cabinet interior is covered with 1/4" plywood "skins" I don't think a full tear out is warranted (again, it should be duly noted that I'm not a home inspector nor a mold remediation expert nor a sink replacement contractor (see idiot as noted above.)

Assume you have a GC? This is on them to figure out and repair. I would have him/her remove the toe kick and take a look, with faucet running, and also get down in crawlspace. I wouldn’t take this lightly as you don’t know if the rock behind the cabinet is a wet mess. I had a leak in a pipe behind the sink cabinet in a rental of mine. Ended up removing all cabinets, remediating moisture damage to floor and subfloor as well as wallboard behind cabinet. Had to remediate mold. They rebuilt the one damaged cabinet and reinstalled them all and I ended up with new counters and floors. Fortunately my insurance covered it and I was out just my deductible. If you don’t get this fully sorted out and you pay the GC in full this will be much more difficult down the road.

So, to confirm, the cabinets arrived perfect and without water damage, right? The water damage showed up after installation and your GC doesn't know where this water came from, right?

Who first noticed the water damage?

Was there a plumber involved or did your GC do this too?

Did GC stop work or just continued, ignoring that there was a leak?

Did your mold guy go down into the crawlspace and use his humidity reader to check if the sub-floor had excess moisture in it?

When we gutted our kitchen my GC found a long term, but very low volume leak between the cabinet underside and the sub-floor. He said it must have been going on for years. The sink cabinet did smell a bit musty, but I assumed it was just due to the cabinets being 18 years old and having smelly cleaning supplies. The damage was quite extensive and we basically had to remove a whole corner of the house where the sink was located, remove all affected wood and rebuild it all. Gotta love remodels and the hidden surprises!

I agree with Charles on this one.

I just don't see this this as water wicking up from the bottom unless your cabinet bottoms are mitered in (which they are not). The side would be falling apart with massive water stains before the horizontal surfaces showed anything other than a hint of water stains. Go run the experiment, just do a simple screwed together butt joint on two pieces of plywood and dip one in a full bucket of water and wait. Then show that to your contractor and ask for some more explanation.

First, so sorry this happened in your new kitchen.

I think it is important to know the cause of the mystery leak. What do the GC or Plumber mean by residual water? When you disconnect a pipe, you will get some water that runs out (my plumber uses a bucket). But when installing new plumbing and cabinetry, how much residual water is there? And if they are working under the sink, don’t they catch it or dry it up ASAP. Seems if it was “residual water” as they describe, they would know and not need to speculate, but fess up and say, yes, we did this and water ran out the pipes etc.

Also do you know the timeline? So the cabinets were sitting in your living room until they were installed. Do you know how long after they were installed before anyone saw the damage? Did you find it or did someone point it out to you? Are you living in the home? Is someone working there every day? Is your sink, disposal and dishwasher installed and working? When was the plumbing done after the cabinets were in place? Did anyone mop up water from the floor? Is there a refrigerator water line under the sink? What is behind the sink wall? Exterior or anther room? Sorry for the long list, but these details are not obvious from your photos.

The amount of damage looks like water was leaking for a while undetected. Leaks in ia sink cabinet often occur at the shut off valve. A slow drip can provide a lot of water Over time. Water may drip down or run along the pipes. A leak could occur at the faucet connection. Did your GC or plumber notice this and fix it? Leaks can also occur in the wall behind the cabinet. This would be harder to find and may require some demo of the back of the cabinet.

So think about your timeline And ask them if they saw and repaired any leaks. Also, if you can provide a few overview photos of the kitchen rough before the cabinets were installed, the overview of sink and trash cabinet, and the under cabinet plumbing and faucet connections, and tell us what is on the opposite side of the wall, it may helpful.

If the plywood is solid and not delaminating, and the GC and cabinet man can fix the stains to your satisfaction, then you may be ok with that from a cosmetic point. Surviving a water leak is one reason why people choose plywood. However, based on the amount of water damage, and that you are told there is still moisture, you still need a water extraction company to set up blowers and dehumidifier to properly dry the cabinets and cavities and address your concern of mold. Good Luck!

@Charles Ross Homes Thank you for letting me know that replacing the plywood veneer is not a burdensome ordeal. I'll also bring up your helpful suggestion of removing the toekick and using a small camera to see if there's any water damage under the cabinets.

@Susan Murin Yes, completely agree that we won't pay the GC until this is completely resolved. That's partially the urgency (other than water leaks should be addressed immediately, IMHO) is that his payment is due upon completion and we are almost complete. But obviously, we won't consider the project done until this water issue is resolved. :)

@chispa Confirming that the cabinets were delivered undamaged and installed pristine (I had to dig through old photos to make sure). The plumber installed the pipes. Someone noticed the water before me and fixed it but did not bring it to my attention. I noticed it a several weeks ago and that's when they told me it was a small leak that occurred during installation and that it's been resolved. The mold remediation specialist went into our basement but was unable to get a moisture/mold reading because there is some plywood in the way. He said my GC would need to remove it to inspect under the kitchen floorboards.

@bry911 Thank you for the helpful suggestion and for reaffirming that this requires further investigation. :)

@dianeski Thank you for your kind words and walking me through your detailed thoughts. It was helpful to organize my thoughts in how to approach this.

I'm waiting to hear from the GC to get an exact timeline of when this water leak was detected and fixed but based on the last correspondence, however long ago the leak did occur, it was apparently fixed within a few hours. He says the water line under the sink was a little loose which dripped into the cabinets.

The sink was installed sometime end of March/early April. I first detected the leak mid-April and brought it up to my GC.

The attached photo of the white cabinet with a silver pipes is a SAMPLE photo my GC provided to show where the leak occurred.

The photo without any drywall indicates approximately where the damaged cabinets are located relative to the sink plumbing. Unless something changed subsequent to this photo being taken (doubtful), there does not appear to be any piping directly in the walls behind the damaged cabinets. I only highlighted the "black box under sink" as reference since it is visible in my original picture.

What's even more puzzling is that the sink plumbing is ~10" to the right of corner where all the black mold can be seen. My husband says it's possible that the water travelled to the corner of the cabinets IF the floor had a slight slope but that's pure speculation (we don't know if it slopes).

I am stopping by the house shortly to take better photos and also meet with my GC. I'll update this post after. THANK YOU EVERYONE!!!!

The GC's photo points to the leak occurring at the shut off valve. A slow leak here can drip down on the cabinet bottom. Water can also run along the pipe and drip down on the back side of the cabinet. Water can run along the space between the back of the cabinet and the wood sill plate at the bottom of the wall, and wick up into the cabinet panels if they sit on the floor. These are possibilities of how the water can leak and run undetected along the floor and then wick up into the material sitting on the floor. In any case,

I think his photo at least answers how the leak occurred and that the GC and Plumber were aware of it at some point and repaired it. The "residual water" they described may refer to the fact that they know the cabinet wood still has moisture.

Since your photos show the wall behind the sink is an exterior wall, it answered my question that it's not really an option in this case to open the back side of the wall for inspection.

You wrote "The mold remediation specialist/home inspector confirmed that there is moisture in the cabinets and believes there is also likely mold (tests to be confirmed next week). "

I think now is the time to get drying equipment in there. The pending mold tests you had done will tell you how to proceed.

I would guess these were sitting in a puddle of water for at least a day, probably a week, prior to installation. I would also guess that these are built without structural toekicks as part of the cabinet, but rather separate legs based on the pattern. I would also advise that this is not superficial in the sense that it is only on the surface. The pattern shows that it has wicked up into the plywood from the bottom and is inside the plywood, not on the surface.. Also, mold would take time to develop. If you noticed this within a few days of the "residual water" incident that wouldn't make sense to me. I would definitely open up the toe kicks to look under the cabinets for additional clues.

UPDATE: The mold results came back and thankfully it is *not* mold! There is definitely water damage so my contractor will be using a dehumidifier/fan/heater (not sure exactly which one) to dry out the cabinets.

They will be removing the toekick and/or pulling out the dishwasher and looking behind/beneath the cabinets to see if there was any additional damage under the the cabinets or on the floor.

The cabinet maker will attempt to sand out the black markings and see if that helps improve the look. If not, I will see if they can put some thin veneers as helpfully suggested above.

I asked the plumber to install a whole-house automatic water shut-off to hopefully avoid any future water damage. :)

THANK YOU EVERYONE! I don't know what I'd do without having so many helpful experts to assist me.

P.S. Should I be looking into installing a drip pan under my dishwasher? My kitchen has hardwood (I would've preferred tile but it wasn't in the budget to tear up the original hardwood flooring in the 100+ year old home and add new tile and subfloors.) :)