I bought this brass ball valve from Home Depot and installed it in the orientation of what I would consider "backwards". I'm not sure if it actually matters and before I close up the wall I would like to make sure orientation isn't an issue with these.

My use of the term "backwards" in this case is when the handle points against the flow of water in the open state.

Model: NSF61-8?

enter image description here

  • Globe valves have a direction, when off, the stem is supposed to be on the outflow side of the valve so its packing isn't under pressure when the valve is closed. Apr 20, 2014 at 23:10

9 Answers 9


If a valve has directionality, it will almost universally be cast as an arrow in of the body, as seen in this globe (aka stop) valve:

enter image description here

I've never seen a ball valve that is directional. If you look inside, you'll see the guts of it are symmetrical.

enter image description here

I would say the general rules of thumb for this are:

  • If you can even change the handle direction, be sure that off is perpendicular to the pipe.
  • If clearance or safety is an issue, then install it in the way that works or is safest.
    • For example, if it's sticking out when it's off and likely for someone to accidentally bump into or get caught on it, then install it the other way so that doesn't happen.
  • If clearance and safety are non-issues, and there are other valves present, then follow the convention of existing valves.
    • If you have pipes that flow in opposite directions it's very handy to ensure the valves indicate this.
  • If there's no existing valves, and no clearance issue, then the most common convention is to have the handle point in the direction of flow.
    • There are probably regional and/or industry-specific variations to this, but as far as North American potable water goes, this is it.

I installed a brass ball valve about 13 years ago with the handle pointing against the flow when in the on position. It has worked perfectly. My valve is female by female so the direction did not matter when assembly the piping. In short: a ball is round so direction does no matter. If a valve must be installed in a certain direction is should have an arrow cast into the body showing the direction of flow.


Pipe fitters in NYC have a local rule that the incoming water be piped to the cast side, leaving water on the side with the seam.

  • Do you know why that is? Feb 8, 2017 at 14:51
  • One less potential point of failure when the valve is closed, I suppose.
    – isherwood
    Feb 8, 2017 at 16:33
  • Yeah what Isherwood says. If the seam cracks where the body is threaded together, the theory is the ball will hold back some of the pressure.
    – Ben
    Feb 16, 2017 at 18:15

Without hunting through all the spec sheets to find your particular valve or at least one that looks just like it (not having a number) I note that none of the spec sheets I did examine at Apollo valve for brass/bronze ball valves indicated any directionality (and in fact, you can usually put the handle on the opposite way if it's more convenient. Perhaps not on that model, looking closely.)

Apollo Valve Spec Sheets

This also matches my experience using ball valves, generically.

  • I have disassembled a few ball valves for cleaning and they have all been symmetrical.
    – Hank
    Apr 20, 2014 at 18:55
  • NSF61-8 is the model number Apr 20, 2014 at 19:46
  • or maybe it's 600CWP Apr 20, 2014 at 19:50
  • 600CWP is the "Cold working pressure" in PSI.
    – Pigrew
    Apr 20, 2014 at 20:01
  • And NSF61-8 is NSF/ANSI 61 Section 8 “Drinking Water System Components - Mechanical Devices (Low Lead and chemical / organics leaching test) Don't worry about it too much.
    – Ecnerwal
    Apr 20, 2014 at 21:22

According to this, their ball valves are bi-directional http://www.apollovalves.com/_products/94ALF-A/IOM_I908900.pdf


I used one on a 1/2" water line supplying an outdoor faucet. It doesn't matter which way you. The one I used was the SharkBite brand from Home Depot. The only indication on it was the direction the shark was swimming


Pointing the handle where the flow comes from is the way to go I think because, you can open unscrew the part of the valve that can be unscrewed without having to remove the valve.


Some ball valves have a drain valve to empty the downstream side when needed. Eg. an indoor ball valve that can shut off water to an outdoor hose bibb on the other side of the wall. Unless, I am wrong, such a valve is marked with an arrow to indicate the correct direction of flow.

  • 1
    redwhitevalvecorp.com/product/… appears to be a counterexample.
    – gbronner
    Apr 21, 2021 at 2:26
  • 1
    @gbronner Thanks. I guess we have to admit that the downstream side isn't necessarily the one to be drained. But if the valve has exactly one drain, the orientation would matter if you want to drain a certain side. Apr 21, 2021 at 23:24

It would seem that a ball valve (at least what I buy) has one end that unscrews showing a Teflon seal which should be facing downstream to properly seal to the metal ball instead of the upstream end which is metal to metal????. The cheapo version of this valve only holds back water that is under pressure.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.