The clause does specifically say that I am waiving my right to sue,
except for small claims.

I'm also considering a special valve (like the Waggs except
resettable...assuming they don't only install the wags) and I'm also
considering a PRV valve (one that allows backflow).


On the other hand, if you're using a licensed contractor and they pull
a permit, I doubt you'll have anything to sue over. A water heater
install is pretty cut and dried.