Little Thought of Spare Parts "Cone Washers"
Recently on a trip, I noticed a drip-drip underneath the kitchen sink when hooked up to city water. Determined the leak was coming from the inlet to the water filter. Disconnected the water filter to look at the male fitting to see if there was a washer. Yep there was and with some trouble I removed what looked like an "0" ring. Fortunately I was 20 miles from an Airstream dealer and it turned out the "0" ring was actually a cone washer that had been overtighten and compressed into the shape of an "O" ring. Bought a 1/2 dozen just in case. BTW the kitchen sink inlet cannot be isolated from other bathroom fixtures and unless fixed either you put up with the drip or have no water. A little inconvenient if you are in the middle of no where.