Phenolic taste

After over 40 batches of pretty good beers, I finally had to dump a whole 5gal batch of beer due to extreme high phenolic flavor.
It feels bad watching that golden nectar going thru the sink hole but it was really undrinkable, at least for my palate.
Several issues with my process could have caused the problem:
- Over sparging the grain, having too low gravity at end of sparge
- Sparging with water temperatures above 170F. Few times my sparge water was at 181F.
- Fermentation at too high temperatures.
- Use of water collected thru a garden hose, which I found was adding a nasty plastic flavor.
- Expired water filter

Here are the changes I made to my process to try to fix this phenolic taste issue that happened to few batches:

- Collect only 4gals of wort from mashing in order to end sparge at higher gravity. That drive my grain bill up by as much as 3lb of base malt, but a cost I'm willing to pay to get better quality beer.
- Making sure my sparge water is between 165 to 170F. Never above 170F.
- Fermenting at lower temps. My fermentation chamber let me do this on a heart beat.
- By-passed the garden hose when collecting my brewing water.
- Replaced my water filter cartridge

Have brewed two batches after these changes and can definitely notice the difference.
This issue was probably on my beers for a while but not noticeable when brewing beers with stronger flavors to hide behind. With latest recipes of very light taste profiles, the phenolic flavor became evident.