PVC and hooks down from under your shelf? They make curved shower curtain rods. Flexible tubing like on the back of your washer. Many materials would work in this space as no one but you sees it and its functionality isn't a huge issue.

A wooden quilting hoop? Maybe.

ML

This is a tough one. Anything flexible enough to bend is not going to be rigid enough to support the fabric.

I had a hose break once in a house I was renting. Fortunately we were home at the time.

The stuff they call Pex would bend and be strong. I'm just not sure it would stay bent. My curved shower rod is made by Moen and they sell them at Bed Bath and Beyond. I think it would be too long for that spot.

Maybe you could put a lattice screen in front of it?

Here is a link that might be useful: Pex

You could also make 3/4 of a square shape if you don't need perfectly curved. You could use copper plumbing pipe since they have pre-made 90 degree elbows.

Alternatively, there are tube/pipe benders out there, so you could find a shop that does tube bending and ask them to bend you something into that shape.

I'd go to a big box store and get 1" brass tubing in the lengths required, plus an elbow. Screw together and fasten to wall using the same brackets you'd use for a closet pole, or use copper van hangers, which are not at all unsightly, to hang it from the bottom of the shelf.

Here is a link that might be useful: brass elbow example

First of all, I'm surprised the shelving goes across the top of the water heater. How can it be easily serviced or replaced? A small closet could be built around the water heater and then the shelf butt into the closet wall......but that's an ideal world! :)

Otherwise, you could do as circus mentioned and use two pieces of pipe with an elbow but instead of putting the $$ into brass or copper, just buy either 1/2" or 3/4" pvc, 1 elbow of the same size, paint it and install. Make an L and attach it to the shelf in one spot.....you could use a hook that catches the pole thru a slit cut in the fabric. Or, just drill a long screw thru fabric and pvc and attach directly to the shelf.
For the ends, use inside mount brackets like the ones below. They come in different sizes.

Another option is to use rings/clips to hang the curtain on the rod, but I assume you're wanting to hide as much as possible.

Here is a link that might be useful: inside mount brackets

A screen? 3 fold. Or folding doors made up like a screen. Mount them to the floor. I would be cautious about using fabric. My water heater is the same. Used a found pantry cupboard, removed the back and painted the cupboard and doors same as walls. There is room to add a couple of thin shelves with a back on, which I put single rows of cleaning products in.

Why not right-angle two curtains, made from the one you've bought? One curtain straight across the front of the heater, and the other perpendicular to it. Is there any reason why that wouldn't work?

I do wonder though: should there be a certain distance between the fabric and the water heater? Same question re: the wood shelf and the water heater. Just asking....

Why don't use ready made drapery panels, gather them up to fit the circumference of the water heater, and velcro to it~~easy smeasy. ;o)

Try a bendable shower curtain rod.

Here is a link that might be useful: Bendable shower curtain rod

What about one of those hoops people use to make a canopy over their bed? Ikea has a 20 inch one.

Here is a link that might be useful: Ikea - Himmel Canopy

Anything you put there, curved like that, is only going to draw attention to the area, even if you don't see the actual water heater, and look odd and awkward. I would, instead, hang a panel curtain out in front of it, from the ceiling. No curved rod needed, no fancy solution.

But honestly, it is a laundry room. I don't find the water heater any less attractive than a furnace or a washer. So for me, not worth worrying about.

I'm with Les on this one. A folding screen would be my other choice.

And I have to agree with what some others have said about the clearance of that water heater with the shelf. Are you sure that's safe and up to code?

Your washing machine looks just like mine. Mine is an old Whirlpool, I think. Yours had the same design "flaw" -- the buttons and dials are covered by the lid of the washer when it's open. Mine has been a real workhorse, so no complaints.

Thank you everyone for the great suggestions! You've given me a lot to think about. I ruled out a screen or wooden structure because there just doesn't seem to be room for it there. I have already purchased the curtain, and my intention (at least for now) is to go very whimsical in that room. If it works out I'll post pictures later. If it doesn't, I'll hide. LOL.

EMT tubing will work, (it's the metal stuff used to run electrical wires. Can be easily bent using the right tool.

once done, paint it with a can of spray paint. You may have to get creative on how you hang it, but most hardware stores should have hooks you can use.

The above picture shows some before and after painting.It comes in 8' lengths, and you can get 1/2", 3/4" and 1" diameter.

If you get it at a local hardware store, you could probably have them cut and bend it for you too.

Box it out with wood, like a picture frame, except
you don't have to do the back wall.
Come out past the shelf in the front just the amount
you need to come out, which looks like a few inches.

Attach the wood to the bottom of the shelf on the
left side and to the wall on the right side...
then go buy some velcro tape and glue it to the wood
and the curtain.
You don't need to velcro the entire
lenght of the wood on both the left side and the front, you just have to do
a few inches, then skip a few
inches...I hope this is clear...the curtain would just
be on the left side and on the front.
You could also cut a top for over the 'new addition' :)

the curtain would also be easily removable for washing.

J.

Macy thanks. Great picture. Really looks like that would work, and maybe not be too expensive either.

Joann, thanks for the explanation. I should measure the curtain because I think it needs to be gathered up on something, rather than lay flat. But I'm not sure. I don't want to cut this curtain.

I might be out of my mind with this whole thing, but I want to try it at least, and see how it looks.

The EMT tubing is about $3 for 8'. The big part is getting someone to bend it for you, though two people and a tree can get it done, just work it bit by bit so it does not kink. The bending tool is the expensive part. DH says many big box stores can bend it for you too, if you bring in the dimensions.

I also like Joanne's idea of putting a partition between the washer and heater (make it removable for if you need to replace or work on the heater). That is very easy if you've got some tools. I'd put the curtain just over the front.

Arcy's suggestion of PVC is going to be the easiest and least expensive to execute. For about $2, you get a 1/2" piece of pvc, which will bend all by itself to a perfect curve when you attach the ends to the walls. It will certainly support a curtain.