
Take a walk down a practice putting green on tour, or indeed at many top amateur tournaments, and you’ll might see a host of players going through their drills accompanied by a little box.
While it doesn’t look like the kind of tool you’d see a carpenter or a bricklayer toting, it is a spirit level and golfers use them to gauge the slope or measure the contours on a putting green.
Now you might ask, do golfers really need to use spirit levels? Some top players and coaches swear by them, but if you’re thinking of getting stuck into a new trend will it get you into bother with the Rules of Golf?
And what else do you need to watch out for if you’re trying to figure out a many layered putting green? Let’s take a look…
Can you measure slope on a green? Restrictions on using equipment

You can use a compass. Did you know that? You can get information on distance or direction from a range finder, watch, or other distance measuring device (unless there’s a Local Rule in place preventing this).
But Rule 4.3a (1) prevents you from doing anything that measures elevation changes, using an alignment device to help align the ball, or using a device that would give you a recommended line of play or help you with club selection based on where your ball is positioned.
A clarification to this rule reveals that you can use your club as a plumb line to help you work out the slope, but that’s where the leniency ends.
You can’t hold or place a “bubble level”, you can’t use a weight suspended on a string to act as a plumb line (have you ever actually seen anyone do that?), and, probably more pertinently for amateurs like us, you can’t place a bottled drink to act as a level.
You might have missed it on the PGA Tour in all the furore about restricting green books in late 2021, but they went further still – setting down new tournament regulations that banned the use of any device that could test the condition of practice greens as well as their use in practice rounds or pro-ams.
But what will happen to you in a competition round if you’re using your bottle of pop to somehow give you a read on how sloping a green is at your club?
It’s a savage penalty – two shots in stroke play or loss of hole in match play for the first offence and disqualification if you do it again.
Have a question for our Rules of Golf expert?
Despite the simplification of the Rules of Golf, there are still some that leave us scratching our heads. And as I’ve passed the R&A’s Level 3 rules exam with distinction, I’ll try to help by featuring the best in this column.
You can read all of Steve’s Rules of Golf explained columns here.
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