test

I need to do a DWV inspection test and need to stop up the system at a backwater valve. What is the best/easiest/cheapest way to block flow at the valve? Do I use something like a clean-seal pneumatic pipe plug to keep the valve’s flapper from opening? Any advice would be a huge help

Specifically the dirt tests.a person pounds a stake into the ground,then sticks a machine with another stake protruding from it clicks it on an bam water content an density.