My raincoat was fully waterproof when bought some 8 years ago. Now it's like a cotton blouse in that it soaks up water immediately.
I have washed it with technical wash and sprayed it with waterproofing spray. It did not help much so I have sprayed on some more. Surely there must be some more sustainable way.
- The spray can itself is a lot of garbage for a little spray.
- When I spray the jacket a lot of spray does not land on the jacket but goes into the air.
- The spray itself is harmful to the environment.
There must be room for improvement on the first two points. I know there exists a special waterproofing wax, but that means making a bucket of the stuff, soaking the jacket and then throwing out a (bucket - a little) down the drain.
Some dry cleaners also waterproof jackets but I don't know if what they do is less harmful.