I'm trying to find either a) water monitor lizards or b) Japanese salamanders in captivity. Does anyone know which zoos or private collections keep them?
If you mean the Japanese Giant Salamander, I don't think there are any in the UK. There are American zoos that keep them, and no doubt plenty in japan that do. Water monitors are more common in the UK, I think this monitor photo taken at Colchester is a water monitor. Monitor Lizard on Flickr - Photo Sharing! ISIS also lists them at Exmoor and Flamingoland, N. Yorks. and Dudley.
Couldn't be certain, they certainly have crocodile/salvador's monitor. (varanus salvadorii I think?). The have lace monitor too, think that's in the tropical realm though.
The water monitors went to Cotswold in 2003. Chester have Green Tree, Mangrove, Crocodile, Spiny-tailed and Lace Monitors, plus Komodos.
ISIS lists the following Japanese giant salamnders in captivity: Buffalo 1.1, Cincinnati 2.1, Detroit 2.2, Washington 0.1, Omaha 1.0, San Antonio 2.3, Toledo 1.0, Osaka 1.0, Tokyo (Inokashira Park Zoo) 1.0, Tokyo (Ueno Zoo) 0.0.3, it is obviously an incomplete tally because the Asa Zoo in Japan for one is not there and they are the only ones breeding them as far as I know here's an interesting link to another forum (from 2003) Andrias japonicus [Archive] - Caudata.org Newt and Salamander Forum water monitors are common as muck, they must surely be the most heavily exploited monitor species for skins, meat and the pet trade. I shouldn't imagine it would be hard to find them through private herptile collectors