I flushed my toilet and it made this terrible knocking noise for abou 5 minutes striaght even after it was flushed. It was so loud I couldn't believe it.

What could be wrong?

Quote:

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Originally Posted by JCMURPHY

What could be wrong?

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Seems there is a problem with air in the system. This happens when the pipe to the roof is blocked and/or the main sewerage waste pipe itself is blocked (a frequent situation if you have your own drain system. Start opening the pipe covers and check if there is a block somewhere.

A dirty job, but someone has to do it !!!

:)

The prevoius answer regarding the evnt stack is not your issue. A vent stack would not make noise for 5 minutes. I am asking myself if its possible you have exaggerated that 5 minute a bit since the toilet should complete refilling in a about one minute. Could you test the situation and time the noise length? It may help us find your problem, I susoect a faulty washer in your ballcock.