500 albums in a basement flood--worth saving?

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.

Thank you all for your comments and helpful suggestions. I decided to start removing them and discarding the wet jackets and sleeves to start...didn't have the heart (yet) to just toss everything.
Next step, if this task doesn't overwhelm me with the other major basement cleanup and restoration issues at hand, would be to borrow or buy a record cleaner. Any reasonably priced volume/speed capable units out there? Is an ultrasonic tank also needed? 

Which type of replacement liner is best: plastic, paper, combo?
BTW, still freaked out from this incident which nearly did me in. Went down to the basement during the heavy storm to check for water as our entire backyard was a deep lake (all our stacked firewood had floated away like an Oregon logging camp). As I approached the steel door to the outside (6.5' below grade in a stairwell) it, with the door frame, exploded inward and shot towards me like a surfboard barely missing my chest. Torrents of water poured in from the backyard over and into the stairwell like Niagara Falls instantly filling the basement. Shocked, my first thought was the electric outlets quickly getting soaked (electrocution), so instead of making a run (swim) upstairs, stepped back and up on a table. As the water kept rising to the tabletop with everything floating and jammed together I made decision to jump in hoping not to get zapped. Barely made it to the stairways up to the house (picture Creature from the Black Lagoon). Water reached to step 9 of 12--6' high. Unbeknownst to us, our 120 gallon water heater had toppled over severing the hot and main cold water feed. Sump pumps were either out of commission and/or overwhelmed, Next day I rented an industrial pump and began pumping outside from the stairwell, but all the time (2 days)  ~ 55,000 gallons of water (7,000 cubic feet) were pouring in from the overhead pipe keeping everything filled.
Water Co. guy finally made it in to discover this and shut the valve. The water reached halfway up the main electric 200 Amp service box, but somehow(?) only 3 GFCI breakers tripped, so we still had some electric upstairs.  Electrician couldn't explain it.

tt1man:

The following link is to a "label saver" that I use when hosing down LP's with with either the water tap or a Waterpik (the teeth cleaning gizmo).

The link is to the "Groovmaster" on Amazon, but there are other like items offered as well.

https://www.amazon.com/Groovmaster-Label-Saver-Record-Cleaner/dp/B00NP0QAOW

I always rinse used LP's with water, before applying a brush, in the event that there are small hard particles which would otherwise scratch the vinyl if I started out with a brush or cloth.

It takes more time (the Groovmaster), but then I don't have to worry about mucking up the labels with water or my DIY cleaner.

I use this with tap water followed with the DIY cleaner (made with filtered tap water) and brushes (rinse with filtered tap water as well).

No RCM (can't stand the noise) and still get excellent results.

DeKay