For our minivan camper conversion we have our own portable sink that we found in a discount store over 30 years ago, and it still works like new. I’m a firm believer that if you have it… use it… or you might lose it! Unfortunately, I haven’t seen a sink “exactly” like ours anywhere.
I’m assuming it must be a three-gallon size (most of them are). Five gallons would get pretty heavy to carry around! This one has its own pump on it. Behind the pump is a small air vent that can be opened to keep it from creating a vacuum. The spout has a cap on it to clean and keep curious bugs out. In the bottom is a small rubber stopper. The sink bowl itself has two levels, and there’s a soap dish molded into the left corner. There’s a large cap on the back with a large rubber O-ring in it to seal the tank. On the bottom there is a channel molded in, and there’s a little white drain hose molded with a sharp 90 degree bend on one end that attaches to the nipple on the bottom of the drain, so that you can drain the water out over the edge of a table. If you need to go farther than that, it could be replaced with a piece of clear Polyvinyl tubing available at any hardware or home center. About 2/3rds of the way up the sides is a 1/4-inch lip, which allows for the sink to be set into a hole in a countertop, if you should choose to do that, but the hole has to cut very accurately. For our cantilever countertop, which pulls out over the back bumper of the van (so you don’t have to bend over when working at the sink), we will make use of that lip.
But since I have no idea who made this sink (no mold marks in it anywhere), the closest thing out there today that will work just fine is one made by Reliance Products, called the Wash & Go Compact 3-Gallon Sink. Unlike ours, which is totally open, theirs has a nice lid on it, that when you lift it, you find several compartments that are a handy place to store toothbrushes, shavers, and other things, plus it has a built in mirror.
Our old sink has a hand pump on it to get water from the 3-gallon reservoir into the sink, whereas Reliance’s sink has a spigot on one corner, and you have to use a glass or other container to put the water in the sink. I’m not saying it’s any better or worse than ours… just different. All things considered, it serves the same purpose. And after much searching it has also been the only other thing out there that is even remotely like ours.
If you want to get a little fancier, Reliance also makes another version with more features, and that is the “On Tap Powered Washing Station Tabletop Camp Sink“ (long name, huh?) It’s slightly larger and bulkier, but it features a tip out cover/countertop, giving you a place on each side to set dishes, and it has it’s own powered pump that you can dunk into any large water container, and have the same convenience you have at home. It even has towel rack on the side plus an extra drain pan. But of course, it’s also about four times the money as the more portable version.
These are the only sinks that we have found that are “unique”. But there are many camping sinks available that are simply “tubs” that hold water. Some fold up or collapse for storage which is a plus, but other than that, all they basically do is hold water. If storage is not a big problem, you could probably use any dish pan to hold water and use it to hold other things for storage when not being used as a sink.
So the choice all boils down to how fancy you want to get. It’s one of the things that if you already have something that will work for the time being, then you can save your money until you see a need for it. Obviously, a place to sleep has to come first.