I had a different kind of leak that isn't related to the washer reservoir on my e70 that I think is worth noting here.

There are also cases where the fluid can leak into the cabin. I searched but all of the forums seem to concentrate on the washer gaskets rather than possible leaks inside of the cabin.

If cold weather washer fluid isn't used then it can freeze and cause problems. I am in Phoenix where they don't even sell cold weather washer fluid (you have to buy an additive or mix in vodka/isopropyl) to the normal summer fluid.

If the line becomes plugged/frozen there is a connection under/behind the driver seat that can disconnect. I was able to access this by unbolting the seat and lifting it out of the way but it wasn't my problem.

Mine turned out to be a split in the line that is in the wiring harness. This harness goes from the passenger firewall over the transmission tunnel and to the driver front kick panel and then down the frame rail to the previously mentioned connection point. I believe it was due to it being taken into the mountains by the previous owner where a freeze burst the line. It was directly over the center console so it leaked water into both footwells (slowly making it hard to find). If you see water leaking from under the driver and passenger doors and you can smell the fluid then it is likely that your carpet is soaked. For me with a slow leak I wouldn't see it even drain until backing up and turning which would shift the water to the cabin drain.....

Here is a picture of the split I found inside the car above the transmission tunnel....


I ordered a replacement line but the normal procedure requires accessing the washer tank by removing the inner fender just like replacing a pump screen/gasket.

For now I have a 1/4" ID rubber hose from the parts store splicing my line (the stock tubing is about .260" and it appears to seal just fine on the outside of the ribs. I sprayed the line and hose with silicone spray and was able to get it to slide down about 3" (much farther than is possible when dry) and then I zip tied it for some extra compression force. I don't think it will leak and it is MUCH less labor than removing the inner fender. I didn't want to use a simple orbit style sprinkler splice because those tend to have small leaks which wouldn't be good under the carpet. BMW has a $20 splice kit for this but rubber hose is cheaper and I replaced a long section given that the splice was in a hidden non accessible location.

Hopefully noone else will encounter this but it should help if they do.... Now if BMW would stop doing stupid things like putting washer fluid lines inside of the cabin...

-Rich