Re: bugs/millipedes in tub drain
If there are breaks in the plumbing then you have bigger problems than insects.
Centipedes and other insects like silver fish or sow bugs aren't known to be amazing swimmers to be able to crawl through the drain pipes and get through the water in the " P " traps.
More often than not the insects are are coming form somwhere else and finding their way into the bathroom. They crawl around the sinks and tubs only to fall in and become trapped.
Look for areas of penetration from crawl spaces , along base boards , sink cabinets , wall cavities, etc,. Many times finding lots of insects that thrive on damp enviorments have resulted in finding problems with wet walls or floors from leaks.
Also here is a link for some information ........
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