Functional Flow and Drain

Just wondering how you guys are inspecting for functional flow and drainage.

Do you run the sink and shower and see what happens to the flow when flushing the toilet?

For drainage do you turn the bathroom sink or tub fully on and see if water drains faster than it fills?

Just wondering what methods you use and if you have any other ideas.

Thanks, Steve

That’s the way I do it.

If it works for the seller, it works for me…and the buyer.

me too. except for the tub. i find that if you run the water fully it runs right over the drain and isn’t allowd down so i either run the shower head, or fill the tub a few inches and let it go while running the lav. and flushing the toilet.


I did one home where the bathroom sink would stop flowing when the kitchen faucet was turned on. Both faucets would stop flowing when toilet flushed and you could hear the water being sucked back in the pipe. Way undersize supply piping.