Premise: Cats are messy beasts. Their owners want to contain as much of their waste output as possible, including most importantly urine and feces. Clay is the method that most owners use because it is absorbent and can be treated with various chemicals to improve its characteristics. However, the downside is that all that dirty clay then winds up in a plastic bag or many plastic bags at the landfill. If even a small percentage of cat owners used clay, the amount per day would likely be in the range of hundreds of tons.
So flushable cat litter is an attempt to decrease that. Flushable litters mainly consist of some organic industrial by-product that has absorbent and/or clumping characteristics like clay. However, because the litter is organic, it can USUALLY be safely flushed and ends up at the sewage plant like so many other organic materials. Here in Austin, the end product for sewage is some sort of homogenized, sanitized solid that can be used as mulch or compost.
I say USUALLY above because if your pipes are already clogged, small, or very old, even flushable cat litter might result in a plumbing bill. So think before you use any of these products.
Walnut shell-based litter:
This is pretty good stuff. It keeps down smell, it clumps nicely, and it flushes without problems.
However, two problems: tracking and dust. The walnut based litter sticks to the cat’s feet, and they tend to track it quite a bit. Not only that, but it’s very visible because it is dark brown colored. And the dust can be pervasive: electronics, A/C filters, every surface in the house. Frequent vacuuming is essential.
Another fine choice for odor, clumping, and flushability.
Interesting that whereas any litter is trackable by cat paws, this type seems much less prone to tracking than the walnut-based stuff. Perhaps because it’s lighter colored, you just don’t see it as much? Also the dust is measurably less; just shovel the brown stuff and then shovel this stuff. With the walnut shell litter, you get a little cloud of dust. With corn-based litter, no cloud of dust is visible.
I will admit that the tracking and dust issues could be related to the color of this material (almost white) versus the dark brown color of the walnut-based litter. In other words, tracking and dust might not be as visible as with the darker colored litter.
This is the most trackable litter of the lot. It comes in relatively big bits, and I suppose the nature of wood is that it’s relatively light. So the kitties tend to track this stuff out of the box quite a bit. There’s also a small to medium amount of dust.
One last quibble is that when used in one of the “rolling cat boxes” (see the picture below) that filters the clumps for you without using a slotted scoop, the wood pieces are a bit large for the filter in the box.
Corn-based litter seems to take the prize for me: not much dust or tracking, clumps well, and works in a rolling cat box. It’s not hard to try the different types out so you may want to do the comparison yourself.