PVA, which like all conventional plastics comes from fossil fuels, is closer to a plastic bottle than a banana. To break down effectively, it needs precise conditions in wastewater facilities. Those conditions don’t currently exist

The plastic industry is pretty demented, they're even putting plastic in tea bags now.

Want to go in the opposite direction while saving an enormous amount of water? Look into laundry to landscape greywater systems. It can be as simple as having an outdoor washing machine that dumps the greywater straight into the yard, provided you're using a greywater detergent like Oasis. There are some other options in the Greywater Action FAQ. Please note that most detergents aren't greywater appropriate regardless of marketing (using the color green, including nature pics or words, claims of being natural or biodegradable), however, the ones that are greywater-friendly are easy to find.