I had a few fungal type ear infections as a kid (due to swimming in floodwaters mostly) before the solution was discovered.
I now keep an eyedropper bottle full of methylated spirits in the bathroom. Squirt a bit into each ear after swimming and never have / had problem since starting using this method. It not only gets all the water out - but kills anything nasty in there.
Of course I don't put anything non sterile into or near my ears in the first place. Especially such things as classic DU favourites like penises.