My Dishwasher Water Line Won't Stop Leaking and I am Baffled

I am at a complete loss to figure out the cause of my dishwasher leaking.  Well technically the dishwasher isn't leaking, but the hot water line going into the dishwasher is.  It is the most bizarre problem I have run into since I moved into this house, and I still haven't figured out what is going on.  I realize a leaking pipe doesn't sound like a weird problem, and I didn't think it was until Friday when we pinpointed the leak location after the Samsung dishwasher repairman came to fix what I initially thought was the actual dishwasher leaking.  First, lets go back a couple weeks to put this into a little context, then I'll describe the problem in detail.

The First Water Leak

A few weeks ago my wife and I decided to finally rip up our old kitchen linoleum floor and replace it with tile.  In the process of doing so, we were finally able to remove the old, leaky dishwasher that came with the house when we bought it, since it was previously stuck due to multiple layers of linoleum being installed in front of the dishwasher.  In its place we bought and installed a new stainless steel Samsung dishwasher.  Here is a picture of the floor and dishwasher after everything was complete.

All was well until about a week after the dishwasher was installed.  One morning right after I woke up I noticed an very loud sound coming from the kitchen.  Upon inspection I found that the dishwasher water pump was running, trying to remove water from the basin, even though the dishwasher cycle was finished.  It was so loud because I had cracked open the dishwasher door sometime the night before after the cycle had finished to let the dishes air dry, and the pump was running with the machine fully open.  Very strange.  While trying to get the pump to stop running including adding water to the pump to try and trigger a water level sensor and flipping the circuit breaker off and on, I noticed that the tile near the dishwasher was very warm.  On a cool morning like that morning I would expect the tile be cool or cold, but this tile was warm as if the dog had slept there all night.  I quickly realized there was a water leak, and hot water had flooded under the dishwasher, the cabinets, and the tile.  I immediately shut off the water, but the damage had been done.  The floor was okay, but there was a lot of clean up work, and the Samsung repairman was called since the nine day old dishwasher is obviously under warranty.

While waiting for the dishwasher to be serviced, I decided not to look at it myself since the dishwasher is under warranty, however I did verify there was a significant leak underneath the dishwasher.  Based on looking under the dishwasher and moving around the water hose, I thought the leak was coming from the dishwasher, but as it turns out, I was wrong.  When the technician came out and pulled the dishwasher out from the cabinet, we found that it was the hot water line that had been leaking from multiple pinhole leaks, a five foot, steel braided rubber hose designed specifically for dishwasher application.  I was the person who installed the hose, so I thought maybe I damaged the hose during installation, either pinching a specific point or stretching the rubber somehow and causing it to fail. Steel braided hose should be able to hold up to quite a bit of punishment, but I just chalked it up to bad luck and figured I would buy another one.  That is when things got weird.

Some Unexplained Hose Damage

Before getting another hose, I disconnected the old (nine days old, but still, old) water line and inspected it.  What I found was baffling.  The hose had been leaking from several points where there did not appear to be any pinching or crimping damage, except that the rubber hose inside the steel braid had actually been forced through the spaces in the braid and created a bunch of little plastic nubs on the outside of the tube.  I have looked and looked online for a picture that resembled this problem, but so far have not been able to find one.  Here is what the water line looked like after I removed it.

You can see the rubber (or maybe it is a plastic, I am not sure) hose forced through the steel braid and has
been effectively extruded to create a bunch of nubs that coat most of the tube.

Another shot of the inside hose being forced through the steel braid.

In the center  of this picture is an area that didn't experience the same problem, probably because it
was pressed against the dishwasher or back wall.

I have never seen anything like this, and neither has the internet apparently.  Some people I have talked to have suggested the water is too hot (water heater is set to 120^o F), or the water pressure is too high (no other steel braided lines have shown the same issue), but either of these seem hard to believe since these hoses are most certainly designed for pressures and temperatures well above the normal house water pressure of 40 to 60 psi and hot water temperature of 120^o F to 180^o F (about 49^o C to 82^o C).  Looking up the exact hose I bought, the rated pressure is 125 psi, and the rated temperature is 180^o F.  Add in a factor of safety in the design that puts the actual design limit higher than these two values, and I cannot believe this is the problem.

The Second Water Leak

Either way, I was looking to reinstall my dishwasher, not investigate this hose failure any further, so I went back to Lowes and purchased an eight foot steel braided hose, getting three more feet just to be sure I didn't over stretch the hose during installation.  This did not take long, but resulted in some extra hose that I coiled in the under-sink cabinet and attached both ends of the tube to the water line and dishwasher.  Opening the valve, I discovered no leaks, and was happy to have a working dishwasher again.  I filled up the dishwasher and ran it, finally getting the remaining dishes in the sink cleaned.

For the next thirty minutes or so I did some other cleaning, then returned to spray bleach in the gap between the floor underneath the cabinets and the new tile we had just installed a couple weeks prior.  While spraying, I noticed there was what looked like new water leaking into the floor from around the under-cabinet sink.  I immediately opened up the cabinet doors to find water, about an inch of it, pooled on the bottom of the cabinet under my sink and water leaking from the brand new hose.  I shut off the water line, grabbed some towels, soaked up the bulk of the water before it could do any real damage.  The leak had returned.

The Second Hose Failed in Less Than Thirty Minutes

Investigating the source of this new leak, I found that the steel braided tube was the source of the leak again, this time in only four spots, two at the top of where the extra tubing was spooled under the sink, and two at the bottom of the spool.  Each pair of points were where the steel of the tubing was touching itself in the spool, and at these points the inside tube had pressed through from both loops of the spool and actually fused together.  It took me quite a bit of force to get the tubes separated.  This was a similar failure method to the first tube, except this time it was only at four (or really two) discrete points along the tube, and it only took thirty minutes or so (possibly less, I only noticed at that point) for the tube to fail.  Needless to say, I am at a loss to explain what is causing the leaks.

Since yesterday afternoon when this leak started, I have spent quite a bit of time looking for similarly failed steel braided tubes, and talked to numerous coworkers, all of whom are either engineers or mechanics.  Not only could I not find anything online regarding this problem, but I have baffled every mechanic and engineer I have talked to.  No one has ever heard of this happening, nor can they come up with a good theory as to what is causing the failures.  As far as I can tell so far, this is a problem that has never happened to anyone before.  Of course I am sure this must have happened to someone, somewhere, at some time, but if it did, I cannot find a record of it.  I am going to continue looking, however, so if I find something I will be sure to update this post.

After the second failure I went back to Lowes and promptly confused every Lowes associate I spoke with, and decided that I need to find a solution that will tackle this problem, even if I am not sure what is happening.  To do that, I just got soft copper piping and compression fittings, which should solve the problem if it is due to either a pressure-related or temperature-related failure.  I have not yet installed it, but one I do this problem will hopefully go away.  If not, I will be completely dumbfounded.

Determining a Root Cause

The only other source of the problem I can possibly conceive is the fact that the electrical line running to the dishwasher (which is insulated) runs underneath and contacts the steel braided line.  Mind you there is at lease an eighth-inch of insulation around the electrical line, the standard insulation you would find on any household electrical line in your walls, but I am thinking, maybe, there is some level of current grounding into the water line, which is corroding the rubber inside the steel braid and causing the failure.  This seems highly unlikely, but I don't think it is due to pressure or temperature, so I am all out of options.

I would have blamed the problem on a bad tube, but this is now the second tube that has failed, and the chances of getting two failed tubes without the entire batch being bad are very very low.  It is possible other people are having this same issue with faulty tubing, but I have yet to hear about anyone having this problem from Lowes employees or the internet.  I suppose time will tell, but I am to the point where I just want to have a solution, even if I don't know what I solved.  Once I get the dishwasher working and the leak problem fixed, then I can worry about why it happened.

If You Know Something, Please Help

I wrote this post in hopes that either someone will come across that has seen this issue before and know the issue, or at least let someone else with this issue know they are not alone and give them some options on how to fix the problem.  Seriously, if you know what is happening here or if you have also had this problem, say so in the comments.  I am an engineer, and I can develop some likely causes, but I am not experienced enough with plumbing to say definitively what the cause is.  Hopefully someone out there can solve this puzzler.

Update: I Have Fixed My Dishwasher Woes

Just a day ago I replaced the steel braided hose with soft copper tubing, and the issue appears to be fixed.  Check out my short post on it here.