Clicking sound in plumbing

[tyclo43]

Hello everyone,
I have a peculiar issue with my plumbing system. When my dishwasher kicks on to drain, a clicking sound begins over where the pvc drain enters the main septic system pipe. The clicking is about 20 feet from where the dishwasher is located. The clicking is a well timed (spaced evenly about .75 seconds apart) and lasts for about a minute when the dishwasher drains. Any help or insight into a possible cause for this would be greatly appreciated. Thanks.

 

[Mike Swearingen]

It is simply minor expansion and contraction of the plastic lines by the hot water flowing through. Don't worry about it.
MIke

 

[Sponsor]

 

[Jadnashua]

After the flow stops, and things start to cool back off, it will click again as it contracts. The pipe is rubbing on something - a hole is smaller than desired, or something is restricting its movement, and when it overcomes the friction as it expands/contracts, it jumps rather than moving slowly and smoothly.