Can DWR be reapplied at the factory, and does it survive washing?

Yes — DWR is applied in the factory finishing line and can be reapplied, and no, it does not last forever. DWR sits on the outer face as a microscopic coating, so washing, dirt and abrasion gradually reduce beading performance; a realistic expectation is a visible decline after around 20–30 home washes.

Two practical points for brands: (1) heat (tumble dry low, or a cool iron) re-flattens the polymer chains and often restores beading without any chemical reproofing; (2) when a true reproof is needed, wash-in or spray-on PFC-free DWR restorers work well. For production, specify a wash-durability test (e.g. beading after 20 wash cycles) rather than only initial spray rating.