Tahoe is a pretty lake to dive. Lots of boats have sunk but for me it is too hard to die, way to cold! I'd never really heard of someone using a dry suit growing up on the gulf coast. I wore a wet suit up at Tahoe and basically turned into a Franksicile! About 15 ft down... BRRRRRRR. Top of the water during late August will be around 65-70 degrees. An interesting fact is the water below 600ft never changes from 39 degrees no matter the time of year.
If I was going to do some light diving I would hit the secret beach on Nevada side or Emerald bay