If you don't mind dealing with your contaminated equipment and value a customer who's pets use the floors as their toilet, DONT say a damn thing, Just pre vac where you can safely, use your UV light with out mentioning it, hit the pee spots with some 40 and or some smell good product and just flush the carpet as best you can.
No water claw promises, no lectures, no mention of needing new carpet or pad, just pat the dog on the head and charge enough to make it worth your while.
They know whats going on most of the time, don't make them feel uncomfortable by pointing out how disgusting they and their pets are.
The second you start itemizing for adding a glug of deo to your HF or $25 per spot to water claw and so much per foot to apply a post Deo, you've probably lost them. They'll keep searching for that laid back cleaner who doesn't have to nickle and dime every job to get by, which probably means their search will never end unless the move to Gardnerville NV.