2RS is a contacting rubber seal. This name is used by SKF and some other manufacturers. Same as LLU really which is used by other manufactuers as the name for it. LLB is a non contacting seal and can let more water in.
Like all things not all bearings are equal. Bearing have grades but the grade says nothing about the tollerance on the seals or how good the seals are. Some 2RS bearings seal very well other do not. The grade of bearings defines the OD and ID tolerances. Not the race tolerance, race material, hardness, ball material, ball roundness, ball hardness, grease compostion......
Generalisations with bearings tell you nothing.
Use a SKF or INA 2RS bearings or an NTN LLU bearing and the water wont get in as easily and the grease is not so easily washed out. Of course if your pressure washing then it all your fault.
be careful where you buy branded bearings from. Plenty of fakes about. You can check you have genuine SKF bearings by authenticating them on their website.
This guy only sells quality bearings. Also has information about seals types etchttps://www.hambini.com/bearings.html