replying to Rusty, John wrote:
I have the same problem. Since we preprinted dishes its not grease buildup.
We have a septic tank so all plumbing in in basement ceiling. It is definitely
the detergent. We have been using the hell packs but will be going back to
liquid Same thing happened to my daughters house. She used powder
detergent. It filled the pipe with a sandy substance, which I assume are the
filler materials added to the detergent

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