Relocation of vanity plumbing

[mikane]

I have to move the waste and 1/2-inch copper water supply lines to the left about a foot to accommodate a new vanity. The existing supply lines run vertical from the floor below. There is a tee on each to stub out the lines. Each line continues vertical from the tee about a foot and is capped off.

Is this riser necessary? Required? I assume its to relieve pressure on a sudden shut off or maybe to minimize water hammer?

 

[Mr_David]

If top is capped they probably did that to prevent water hammer.

Maybe you don't need it. Maybe they just installed it as a precaution.

But WHAT IF? you eliminated it and wished you hadn't.