Crypto detection limits

[wick at cris.com]

I am interested in determining typical detection limits for labs analyzing cryptosporidium in environmental water 
samples. Specifically, what detection limits are commonly found for testing raw, finished and backwash water 
samples at water treatment plant?.  I realize that the limit will vary depending on the water turbidity, however, a 
given source of water will probably show similar detection limit under most situations. What detection limits have 
been found in your water sources?

Jim Wick