I foolishly used liquid soap and baking soda when I ran out of dishwasher tablets for my Bosch (model SHX68T55UC). It worked and I bought more dishwasher tablets after about 3 days and started using them. Within another day I got the code E: 15 which means that there is water in the unit that has floated the leak detection sensor at the bottom of the unit (below the main bin). There is a good YouTube video (see https://youtu.be/8kW4jkHln3k) that explains how to fix this. It's basically just a float that rises in the water and trips a sensor. I cleaned it all out and put it back together and the code was gone....

However, it came back, and there is water in the far back of the under part of the unit (where all the electronics are, NOT the main tub). For the life of me, I can't find the slow leak. All the tubes and connections seem fine. The insulation at the back of the unit is soaked. I believe it's leaking somewhere at the back, and this water slowly seeps towards the flood sensor and trips it. Of note, I can do a load (or two?) before enough water accumulates to trip the sensor.

I'll add a picture soon to make it clear I'm looking at the under part of the dishwasher, not the main tub where you put dishes. It did occur to me that the main tub could be leaking, but the unit is only 3 1/2 years old (but out of warranty unfortunately) and it sure seems like a coincidence that I recently used liquid dish soap. I'm thinking I still have a problem from the liquid soap OR when cleaning out the area around the flood sensor I did something stupid. Thanks, Dave

Update AND Pictures!
Worth mentioning that it only seems to accumulate water when I'm running the unit. I left it off and watched for several hours and could not perceive any more water. So I think that rules out the inlet water? The back right corner is what seems to be getting wet, which is weird because I don't see any tubes/connections there. I believe the water then flows downhill to the left back corner and to the float sensor.

Update #2. I inadvertently did a test that I think provides a ton of clues. I clean everything up in the lower compartment (the area with the electronics including the float sensor). I ran it on rinse cycle hoping to see where the water was coming from. Very hard to see as the back insulation seems to slowly get wet but again, no tubes around there. The inadvertent test was this: I had to leave for work so I turned the unit off. I verified there was no appreciable water in the lower compartment. Since I turned it off prematurely I had water at the bottom of the main tub (where you put dishes). When I came home several hours later, the lower section was filled with water and the float switch was up (which gives E15 code). So I think there must be a leak somewhere between the upper main compartment where one puts the dishes and the lower section where the electronics is. This means that my previous assertation that there is no problem unless the unit is running is wrong! If there is water in the dish area, there is a problem! I'm guessing that while running, most of the water in the dish area is pumped away to the sink drain. The problem is actually worse if you leave standing water in the dishwasher as I inadvertently did. I'm not opposed to replacing gaskets etc., but does anyone have advice on what to check out first? I would think this latest test rules out pumps, propellers, washers etc. Back right corner-note wet insulation

Back right corner with insulation peeled away

Back left corner and float sensor

  • I assume you have checked all filters and screens? Dishwasher detergent has chemicals that help break down food so it can pass through the filters and pump. Using the wrong soap could have caused a clump of something to form and make a clog somewhere.
    – JPhi1618
    Commented Nov 4, 2019 at 17:14
  • 1
    You may have to flush the soap out with several uses . Liquid soap last much longer than the standard tablets or powder. You got lucky when I did that as a kid there was a 4’ high wall of suds in 1/2 our kitchen.
    – Ed Beal
    Commented Nov 4, 2019 at 18:05
  • Yes, I have checked filters and screens. But will double check. Thank you! It's bizarre to me as it seems to be getting wet at the back of the unit. In fact, I notice it getting wet at the back on some insulation. For the life of me I can't see where the water is coming from. Somebody suggested that it's just the insulation itself leaking water. Perhaps they are right but it seems like more water appears as it runs.
    – Dave
    Commented Nov 4, 2019 at 18:09
  • Ed, I followed a recipe from Google that called for just a few drops of liquid soap and baking soda. Just a few drops to avoid the suds problem you mentioned. It's possible I suppose that the liquid soap has nothing to do with the problem and it's just a coincidence. That is, perhaps something just started leaking? But it's definitely a coincidence. I wish I understood how liquid soap could cause a leak. I understand how it causes suds, but leaks? Thank you for the comment.
    – Dave
    Commented Nov 4, 2019 at 19:33
  • If the unit is off-level, water from the front could flow to the back, and the wet insulation looks like wicking action. Is there any indication that something is spraying? Check that the door seal has not moved out of place and also check any "spinners" or sprayers internal to the unit that may be jammed/off kilter/being blocked from moving when loaded. Combinations of these things are usually the culprit for leaks in my own experience
    – Yorik
    Commented Nov 5, 2019 at 19:30

1 Answer 1


The main penetration of the tub that is below the waterline is the sump assembly. The sump assembly is comprised of the pump, heater, sensors, and other components. There is a main sump assembly seal that prevents water from the tub from leaking out. That would be the first thing I would inspect.

To further diagnose I would disconnect the unit and remove it, set it on sawhorses so I could view the lower components, then fill the tub and try to locate the leaking component.

NOTE- there are numerous other components that could be the source of a leak like your's (e.g. pump-to-sump seal, pump impeller seal, circulation pump assembly/volute seal, etc.) Disassembly of Bosch units can be tricky; not always intuitive. I suggest using your "Google-Fu" to check some online videos, such as this one: Bosch Dishwasher Circulation Pump Repair

  • Thanks Jimmy. I have checked it out a little bit more based on your answer. It looks like it's leaking from the base of sump assembly (very near the bottom of the dishwasher). That's why I don't see any water dripping down from the dishes section and don't feel any water on the sides or top of the lower electronics section. Frankly I might throw in the towel on this one. My brief research indicated that repairs guys charge a fortune if they have to get into the sump assembly in any way (motor, gasket, etc.) , and I just don't see the ratioanalle of fixing a machine that is only 3 yrs.
    – Dave
    Commented Nov 9, 2019 at 16:30

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