DWV water test

How do you water test a DWV system? I have completed my DWV system in my new home and would like to test it.

If I insert one of those inflatable test plugs through the clean out in my crawl and all opening for sinks, tubs, and toilets then fill it with water. How do I drain it when finished? If i open the clean out to remove the plug I am sure the water will be all over my crawl before I can remove the plug.

I must be missing something here.

The test ball goes on the uphill side of the cleanout...
Yes you do get wet when you remove it!
Hopefully most of the water goes down the drain.
Good thing its only water!

test

You get what is called a "screw in test ball". It replaces the cleanout plug and you inflate it to seal the pipe. When it comes time to drain the water, you release the air and the water drains down. Then you remove the test plug and replace the cleanout plug. If you use a conventional test ball, be sure to hold it in place with a stick or rod when you release the air or it will slide down the pipe past the opening. Then you will get flooded, but also have the chore to try to pull the plug back to the opening to extract it. That can be a challenge because pulling the chain will try to rotate the plug rather that pull it backwards.

Just to make sure I have this right. I have attached a pic.