load test them for you. If your battery took that much "water" I'm betting the plates were exposed and that can lead to them warping and a battery that won't charge up.
Plus a battery that has been drained of charge multiple times is more liable to be unable to accept a charge than one kept fully charged.
3 days to drain the battery is a very short time. Done anything to the car recently? Any aftermarket electronics?
There are lots of batteries that fit our cars
listed here.