Aberican municipalities use floculation to settle out particles of debree, not filtration. Plastic has a nearly similar mass to water so floculation works poorly on it very dirt.
If you are worried about it, put a whole house filter on with a 5 micron filter pack. I like the “big blue” system.
All surface water used in potable water supplies in the US generally must be filtered. (i.e. ponds, lakes, rivers, reservoirs,...etc)
Floculation simply increases the aggregate size of the particles for settling or filtration.
Ground water, may also be filtered, but generally ground water from a well, or from an aquifer, has already been filtered by the sand and gravel and sediment it flowed through in the aquifer to get to the well inlet.
Generally speaking, plastic is inert, not soluble in water.
Also plastics typically do not break down into smaller plastic fibers or plastic sediment. Plastics tend to shrink when heated up, because their molecular chains collapse upon themselves. May want to boil the water and extract the steam, re-condense and dispose of the solute as wastewater for filtration.
Also, why filter whole house? I bet 95% of house water isn't going into us.