I don't have that brand but have others with what they call DWR and there's no need(with what I walk through) and will probably cut down the pants ability to breathe significantly! But I know the kind of wet conditions you are talking about, but I would wear them a couple times and see if they don't work as is before you try treating them. Also Nikwax makes a wash to restore the DEAR to outdoor fabrics. Rust-Oleum makes a product called Never Wet designed for patio furniture fabrics that might be better than silicone and it's phenomenal for water proofing feathers too!