500 albums in a basement flood--worth saving?

I would @ a minimum remove them from the jackets/sleeves ASAP and then decide their fate later on.

If you don't they will most likely grow mold.

Not certain how to store them to dry, but perhaps someone else will come up with something feasible.

DeKay

Wouldn’t the records warp after getting wet?

No such thing as relatively clean flood water. What you will find, huge amount of grit got in there. No record cleaners on the market are designed to clean records that have fine grit caked on from being soaked in sludge. The problem is being covered with incredibly fine grit abrasive particles that will be hard if not impossible to clean off without scratching the vinyl in the process. If you have a few treasures it might be worth a try and who knows you might get lucky, might be only a ten minute multi-step process to do each one, and they might even come out fairly quiet. But odds are, complete loss.

None of mine warped. Took about 4 days in the garage, with fans after a couple days of dripping. It was 80-90 degree weather here. I didn’t have flood water though, I never did get any molds. There were a few that were pretty dirty too. Bubbler tank, just like an aquarium, until they look good,hand wash UNDERWATER with mild dish soap, inspect, then ultrasound, test and label.. Work pretty good, Actually real good.. Some of those records, were NEVER used, maybe twice in there whole life.
Polka music, native Irish, and Highland music..

Regards

No.  An LP won't warp just from getting wet.  That's why RCMs don't warp LPs.  Extremes of heat and cold and storing LPs incorrectly will warp them.  To the OP:  It depends entirely on how precious these LPs are to you.  Since it was fresh water, and since presumably the jackets protected the LPs from extremes of dirt and debris in the water, I doubt they are damaged.  But the work of salvaging them will take a couple of days and ought to be done ASAP.  That's where you have to decide whether the work of removing all of the LPs from their sleeves and re-storing them in fresh sleeves is worth your time an effort.  It wouldn't hurt to rinse each LP in an RCM, or even just under clean cold water from a tap, before re-packaging them for storage.