Ah, the litter box -- essential to every home where cats spend time indoors, seemingly simple, yet often fraught with complexity in terms of what it takes to create an ideal setup.
I never expected to spend as much time as I have since the current resident felines moved in figuring this out, but seeing as we've had zero problems in that department so far around here, I consider every moment spend pondering the intricacies of litter substrates, containers, and locations, to be well worth it.
I have to admit that when I was growing up, I lacked the appreciation I currently have for the importance of creating restroom facilities for cats that truly appeal to and meet feline criteria. Poor Tim (our family's Siamese guy, who we had from when I was in 5th grade through my senior year of high school) often had to put up with some truly terrible box conditions simply because we humans were not vigilant enough about keeping it clean.
Granted, at the time we did not have the wonderful invention that is clumping litter, but still. Since the box was in the downstairs basement bathroom it was very easy to just forget about it for days, and not give it much of a thought until Tim chose to communicate his displeasure with his toilet conditions by, say, crapping right in the center of my beanbag chair (for which I don't blame him one bit!).
In any case, I have learned (from my youthful irresponsibility and from a variety of cat-related books and online resources) a number of things that I believe have permitted a much better environment for the felines who now share my home. Among these valuable pieces of information are:
(1) Have more than one box.
This is absolutely essential in a multi-cat home (and possibly essential even if you only have one cat, if said cat is very young, very old, ill, or if your home has multiple stories).
One of the most eye-opening things I've learned of late has been just how very important territory is to cats, and the litter box is often one of the most contested and worried-about bits of real estate in the feline's home environment. Hence, one litter box for 2 or more cats is pretty much a recipe for territorial disputes, quite possibly of the smelly variety. Moreover, if such disputes are taking place, it's a sure bet the kitties involved are going to be stressed and hence unhappy much of the time, which obviously isn't good.
Luckily, there's a simple solution -- multiple litter boxes (and this is important) placed in different rooms, or different areas of the house. This effectively "splits up" the pottying territory, making it impossible for more dominant cats to "guard" the only available bathroom.
Furthermore, having multiple boxes actually makes for easier cleaning, as odd as that may sound -- but it makes sense when you consider that each box is likely to have a much lower concentration of waste.
As for exactly how many boxes, that is going to depend on a number of things. Most guidelines I've read as of late suggest "one box per cat, plus one extra". And my guess is that this is a wonderful guideline to follow, likely to pretty much guarantee zero territorial battles over bathrooming space.
However, I must admit that I have not personally managed to fulfill this guideline in my household -- we only have three boxes currently. I would love to have another box, but I can't for the life of me figure out where to put it. If the (one and only) bathroom were larger I'd put one in there, but the size it is now, there's literally nowhere to put a litter box where it wouldn't interfere with opening and closing the bathroom door.
The living room, meanwhile, is a "play zone" and the kitchen is a "food zone", so I don't want to put litter boxes in either of those rooms, because cats generally don't like to crap where they eat or play anyway. So for now we are sort of stuck with the three-box arrangement. I also realize that my litter box locations are not the best (two of them are in closets, albeit ones that are never closed) in terms of providing the cats with maximum visibility whilst going about their business, but I couldn't exactly put them where everyone would be tripping over them. So I did not have a whole lot of options in that regard.
[And my house isn't tiny, it's just laid out such that the majority of the area is a big, open space (living room plus kitchen) and the rest is divided up into very small rooms connected by a short hallway.]
So far all the cats seem fine with this three-box arrangement -- nobody has complained (and by "complained" I of course mean "crapped in my shoe to communicate their displeasure with the facilities"), at least. Plus, since Nikki has yard access, she can do her business outdoors (at least on some days); thankfully she prefers un-used (by humans) corners of the yard as opposed to the vegetable garden for that purpose. But I just keep thinking there must be some creative solution I haven't thought of, whereby I could stick another box somewhere just for that extra peace of mind it would provide.
Also, I have to say that figuring out where the boxes will go has definitely solidified my sense of my house's "cat-carrying capacity". I would definitely not want to be figuring out where I'd put six or seven litter boxes, which tells me that four cats is probably my ideal maximum for this living space, so that is what I am sticking to.
(2) Get your litter boxes at the hardware store, not the pet store.
These days when I go into the pet store, I almost have to laugh at the kitty bathroom facilities they offer. They're so small! And the sides are so low! Or they've got elaborate covers over them, inside which I cannot see how an average-sized cat could even turn around, let alone poop comfortably. And they're ridiculously expensive, for what they are.
I've had much, much better luck with (a) large plastic storage containers (20 gallon or larger, with FLAT bottoms, not the kind with weird grooves in them) -- the high sides do a worthwhile job of reducing "litter scatter", and (b) cement mixing pans.
Currently I have two storage-container boxes and one cement-mixing-bin box. They were all cheap, cheap, cheap (under $10 apiece, if I recall correctly) and all the cats here use them enthusiastically.
Below are pictures of my various "litter box stations", with a bit of commentary on each:
Box #1 is located in the spare bedroom/"library" (it's a very small room with bookcases taking up one entire wall, a futon under the window, and a small table in front of the futon). This one is made from an Ikea Snalis storage box, which we've had since Cora and Brodie were tiny (back in October 2009). It has held up very well so far and this box gets a lot of "traffic", even though it's a bit smaller surface-area-wise than the other two boxes. So I am guessing the kitties like the location.
The one hurdle about this box's placement I haven't yet had to deal with (but have thought about) is: what if we actually have overnight guests at some point? Matt and I are kind of hermit-y and don't have many people over, but it presumably could happen. And my guess is that most people would not want to sleep in a room right next to an evening feature of "Kitty Takes A Dump At Midnight".
But I know cats don't like having their boxes moved all of a sudden and I certainly don't want to stress them, especially given that the mere fact of having guests at all would probably wig them a little.
So I am guessing that what I might do is plan way ahead for any overnight guests, and move the litter box out into the hallway (as gradually as possible). But in the meantime, I will certainly leave the box in that room because it's probably the least used-by-humans room in the house, making it perfect most of the time to house a kitty bathroom.
Box #2 is a clear Rubbermaid storage bin. Slightly larger than Box #1, and with the "step-in cutout" on the long side of the box rather than the short end, this one is located in the hall closet next to the bathroom. This closet has 2 sliding doors but we never close the one on the litter box side, whereas the other side is pretty much always closed because that's where the water heater is. So it's really more like the litter box is in a little "alcove" thing in the hallway, which is a good place for it logistics-wise because that way I'm not liable to accidentally step in it.
It actually took the kitties a rather long time to notice this box was even there, though that could be simply because it's the newest of the three boxes and by the time I added it to the set, everyone had become accustomed to using the boxes in the 2 other locations. But they do use it now (at least, the three younger cats do -- I've never seen Nikki even acknowledge Box #2), and for some reason it seems to get a lot of night-time traffic.
Eventually I would like to perhaps take that one closet door off completely and perhaps paint the shelves above the box (making a tidy little cat-nook; I already use it to store extra litter and other cat supplies in plastic containers). But for now it does the job as-is.
Box #3 is a large black cement mixing pan I got for about $6 at the little hardware store down the street. If the sides were just a bit higher (they're about 6") I would probably consider it to be the Most Perfect Litter Box Ever. It has a ton of surface area (which was the main reason I got it -- my boy cats especially are big guys, and still growing, and I wanted to have something they'd be able to turn around in, etc., once they reached full size). It has a smooth bottom with NO grooves, which is rounded at both ends, so scooping is very easy, and litter clumps are far less likely to break up.
(There is a commercially available litter box with a similar design, but you will pay more for it than you would pay for a cement mixing bin. Its sides are a bit higher than those of the cement bin, though, so for some people that alone might be worth the additional cost.)
I have this box placed on one side of the closet in the computer/office room. Matt and I completely removed the doors from this closet (they were huge mirrored affairs that Matt disliked from the get-go anyway) so it is not a very "closety" space anymore. All four kitties seem very pleased with Box #3, especially Nikki, who likes to be able to see all around her while using the facilities.
Mind you, none of my cats seem to be the types to stick their butts over the edge of the box and "miss" or produce horizontal "over-spray". If your kitties have these sorts of tendencies, the sides on the cement mixing bin might be too low for you to consider. As it is, I am glad that I had a "corner" location to place this box in (I attached plastic shelf liner to the adjacent walls, just in case...) because there is definitely more scatter from this box than from the storage containers. But I don't really want a higher sided box in that location because it's right near the doorway to the room and higher sides would probably eliminate the visibility advantage. And really the scatter is not THAT bad, as long as I keep on top of it with the mini-Dyson-vac!
(3) Avoid covered boxes.
Now, there are exceptions to this one...some shy or self-conscious cats prefer to do their business in a cave, so to speak. But the majority of cats are far less inclined to appreciate a cover on their litter box, and more inclined to appreciate the extra head-room, visibility, and fresh-airiness that a lidless box provides.
I have known many cats who use covered boxes without complaint, but seeing as I wanted to pre-emptively prevent litter box problems when it came to my kitties, I decided to go with lidless boxes from the get-go. Which is one reason plastic storage containers are so nice...they provide all the litter-scatter protection of a covered box without the cover!
Plus, not having a cover makes the box way easier to clean...you don't have to disconnect or remove anything, whether you're scooping or dumping and scrubbing the whole box. There are no little plastic clasps to break or get stuck, no litter-cement stuck in odd little nooks and crannies...just smooth surface all over. Lovely, as such things go! And of course there's the advantage of you being able to SEE the poop when it's there, rather than having it build up out of sight, creating much grossness for the cat and also for you later when you finally go deal with the mess.
(Oh and regarding electronic "self cleaning" litter boxes? I've never tried one, and don't plan to. All I can think of when I see those things is how they're full of small and moving parts that would ALL have to be periodically cleaned, which I know would be a huge hassle for me. I much prefer the low-tech simplicity of "all one piece" boxes. Your, and your cats', mileage may vary, though.)
About the only covered box I would ever consider would be one with holes, or mesh, on all sides, to allow for air flow and visibility. But there is no way I am going to want to "trap odors inside"...that right there is a major recipe for litter box avoidance. Not to mention the fact that, in a multi-cat situation, covered boxes provide the perfect opportunity for ambushes, which can lead to shy cats avoiding the box altogether and deciding that your laundry basket (or worse) makes a safer toilet.
I just didn't want to set up the conditions to foster ANY litter box avoidance, and for me, the fact that occasionally I have to walk by a box and see (and smell) a turd sitting there is MUCH preferable to stressed, box-avoiding kitties and probably extra messes to clean up in places much less scoop-friendly than the litter box.
(4) Scoop more than once a day.
This is especially important in multi-cat situations (singlet kitties may not require it, but it depends on the individual cat). I scoop all boxes twice a day minimum, sometimes more. It's part of my morning routine and evening routine now, and I would feel very weird if I didn't do it. Letting waste build up not only makes box avoidance more likely, but gets awfully smelly very fast, and can even end up costing you (as you will surely go through more litter that way).
Seriously. You do not want your kitty to have to step through piles of his/her own waste in order to use the toilet. If you need help managing litter boxes, get help. (I realize this is easier said than done, though, if you need help that badly, so I do not mean to denigrate anyone's situation). I guess what I'm saying is, keeping the box inviting (which means clean) should be a priority, not an after-thought or optional consideration when it comes to creating a good home for cats.
(5) Avoid scented / perfumed litter, "pet area" air fresheners, etc..
This one was very easy for me as I myself can't stand the smells of most scented products, litter included. Plus it is just patently apparent to me that covering up an odor is not going to fool a cat! Dirty litter is still dirty, no matter how much it might smell like the choke-inducing soap in your Great Aunt Effie's bathroom cabinet. Same goes for potpourri-spray around the litter box, or scented candles or whatnot. No cat with a crap-filled box is going to smell the aroma of Cinnamon-Citrus Breeze and think "oh how wonderful!" More likely, the cat will use the box grudgingly, if at all, and become that much more liable to go seek out a less asphyxiating bathroom location.
(And again, YMMV on this one -- I am not trying to be a judgmental zealot here, but it just seems to me like common sense that you wouldn't use a heavily-perfumed product in a toilet facility for someone with an extremely keen sense of smell. Just as with covered boxes, though, I have known cats who don't seem to mind scented litter. But as I personally can't stand the stuff myself, and as I'm big into that whole prevent-problems-before-they-start thing, I just figured I was better off finding an unscented litter and sticking with it.)
As for what litter substrate I use? Currently I am using Swheat Scoop Multi-Cat. Mostly I started out with this litter because it was the only one I could find that was unscented, indicated it was "safe for kittens", and also clumped. (Clumping clay litter is not recommended for kittens, as supposedly it can cause intestinal blockage when licked off their paws).
I'm more or less happy with it, though it would be nice if it clumped a little more firmly. It is not dust-free but it's a heck of a lot less dusty than any clay litter I've come across. And I like that the bags are much lighter to carry than an equivalent volume of clay. I don't see any reason to switch brands, and I wouldn't want to do so suddenly anyway, because that's another thing that can lead to box avoidance ("hey, this isn't the stuff I usually crap in!").
(Note: I have also tried the non-multi-cat variety and confirmed that there is a performance difference -- regular Swheat Scoop definitely does not smell as fresh for as long as the multi-cat stuff. After a few days, even with regular scooping, it starts to smell like a gas-station restroom. So I would recommend trying the multi-cat Swheat Scoop if you're heading down the wheat road anyway, even if you only have a singular cat.)
Some people have recommended World's Best Cat Litter to me. I am sure it is a fine product but I can't use it because of Brodie's corn intolerance. He is so sensitive to the stuff that even two or three corn-based treats will give him the runs, so I certainly wouldn't want him walking around in corn-based anything or cleaning himself with that stuff all over him. If your cat doesn't have this corn issue then you would probably be fine with WBCL (and it might be something to try if your cat instead has a problem with wheat, as some cats do).
(6) Flushable Litter Generally Isn't.
This is more of a human-relevant concern than a cat-relevant concern, but seeing as our sewer cleanout recently backed up into the front yard, I figured I would point it out so others could hopefully avoid a similar fate. It is probably fine to flush individual poops down the toilet (I do this sometimes still, and have no problems), but you definitely do NOT want to be putting giant pee-clumps down that drain.
My guess is that even if you let it sit for the recommended 20 minutes, that is still a heck of a lot of sheer matter for the crapper to "digest". Even a nominally "flushable" litter, when flushed in the quantities you'd expect from four cats, can lead to a plumbing nightmare, and most people I know would prefer to avoid nightmares of that variety.
So unless you know you have super-mega-industrial piping in your home, you probably just want to toss the used litter clumps into the trash. If you are worried about biodegradability, you can actually get biodegradable bags for this purpose (they sell them to pick up doggie waste with). And you don't need to spend lots on a special receptacle for bags of litter, either -- a regular diaper pail or trash can with a tight-fitting lid (not one of those swing-type things) will do the job just fine.
And as for environmental concerns, there appears to me to be no "perfect" litter or way to deal with cat waste. Some people don't recommend flushing any cat waste because toxoplasma parasite can harm sea otters. Others claim flushing is better because that way you don't have anything sitting in a landfill. I would suggest just doing your own research and balancing whatever you find with your cats' and your individual needs.
Now, note that none of the above were my original ideas...aside from the "this is what I'm doing in my home" bits, I am just repeating advice I've heard/read in far too many places to reference here, trying to spread the information around so that more people are likely to encounter it.