Toilet drain problems - found sandy substance build-up in drain

We've been having problems with our master bath toilet clogging. Seems to clog much too easy. So I removed the toilet and found a sandy substance building up in the drain pipe. I scraped it out but I'm not sure how far it extends down the pipe since it bends about 6" under the floor.
Our hall bath toilet is also having simliar issues although I haven't removed it yet.
Any clue what could be causing this build-up? Is it hard water or something?
Thanks - Jim
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Any construction in the area which involved the water company repeatedly working on the pipes? And, how old's the house?
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budne1 wrote:

If you had to scrape it out it is probably calcium carbonate. Your water is hard?
--

dadiOH
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