Are toilet tanks interchangeable?

I managed to crack the tank in my master bathroom so that it doesn’t hold water and is no longer functional. I’d like to save the expense and replace it myself, but can’t find the answer to this question on any of the sites I’ve looked at. The toilet was installed 30 years ago and I’ll replace the entire thing if necessary, but I’m looking to get out cheap on this.
Thanks in advance.

Not generally, particularly after 30 years. However, you can almost certainly manage to replace the entire thing for around $50-60, if you do the work yourself and purchase a basic, no-frills model. It’s not all that difficult to do, but it can get a bit messy.

I had the same problem this summer. Cracked tank - and it was the higher-volume tank that I wanted to keep - and I was broke. Several people told me no way was I going to be able to just get a new tank unless I hunted around and who has time to hunt around?

Go to Home Depot and walk down the toilet aisle, past the $400 toilets, past the $150 toilets, past the $90 toilets and get what I like to call “toilet in a box.” $56 and it comes with innards AND a seat.

But…the innards will be insufficient so pick up another set ($10) and unless you can live with a reeeaally shoddy plastic toilet seat, pick one of those up too ($10). Get a new wax ring too ($3).

You can do it yourself, no problemo.

In addition to the above, measure the offset from the base of the wall behind the toilet to the bolt centers of the closet bolts that fasten the bowl to the floor. There are two common standard offsets: 12" and 14". You want to make sure you get the proper replacement. If the closet bolts are rusted (and even if they aren’t), you’ll want to replace those too–just a couple bucks. After you get the toilet pulled out, scrape as much of the old wax ring out as possible–this is the messy part. Check the closet bolt flange to be sure it isn’t cracked or otherwise damaged. And of course, don’t forget to turn off the water at the shutoff before removing the water line going into the tank. Once the water is off, you can just flush the toilet to drain out most of the water–hold the flush handle down until as much of the water in the tank as possible drains out. A caveat: When assembling the bowl to the tank and bolting the bowl to the floor, don’t overtorque the fasteners or you risk cracking the porcelain! Hand tight plus 1/2 turn is generally sufficient. If there is some leakage at the seal between the tank and bowl, tighten in 1/4 turn increments until the leak stops.

If you’re in a big city, most of them have used plumbing supply places that stock things like this. But many of them are called ‘classic’, ‘retro’, or ‘antique’ plumbing fixtures, and they want to charge you inflated ‘antique’ prices for their stock. It might be cheaper (though more work) to buy a whole new toilet and replace the entire thing.

To actually locate a tank, you will need to know the manufacturer, model, & size of your current 30-year-old toilet. You’ll have to look around to find that – it’s often on the inside of the tank lid or molded into the inside of the tank. Also measure everything, and take those measurements with you when looking.

If you do find the tank you need, it’s quite possible that you will have to buy the whole toilet, including the bowl part that you don’t need. After all, the store probably doesn’t want to break up the set – it’s much harder to sell half a toilet.

Most of the big-box stores like Lowe’s or Home Depot sell tanks and bowls separately, so this shouldn’t be an issue, provided you can actually locate the matching tank. Might be a different story if they have to special order it for you.

Before you go to the hardware store, check with your water department. You don’t say where you live, but here in Santa Fe, the city gives out free low-flow toilets. Since we live in a desert, it’s worth it in the long run.

Good point. I got three new (and quite decent) “TOTO” toilets for free from the water district. They weren’t the slightest bit fancy, but they’re definitely a couple steps up from the $60 “John-in-a-box” and in the past year and a half, we’ve only managed to plug one of them once.

Beware of cheap toilets - they will clog up every chance they get.

Also, when you remove the old bowl, be very gentle, don’t just yank it outta there, you can crack or break the drain pipe going to the closet flange. Plumbers live for that kind of thing, and I have seen this happen on jobs where the homeowner was a bit hasty.

It might also be a good time to replace the shutoff valve and line. Again, be careful.
In addition, if you have been wanting new tile in your bathroom, it would be a good time to do it, as you have the bowl out anyway. And before you remove the toilet, flush it and when the water is at the bottom, close the valve. Less mess.

30-year old plumbing? leave it to a pro. Plumbing is one of those crafts where the right tools make all the difference and a minor slip can turn into a royal nightmare. Calling a pro might be the cheap way out.

Part of the problem here is that a 30 year old toilet was engineered around a high volume flush. Geberit manufactured a universal replacement tank which worked very well on older toilets, but it’s not legal to sell the large volume tanks any more, and a 1.6 G tank isn’t likely to afford sufficient volume for a bowl assembly which wasn’t engineered to function with it.

I had the exact same problem a few years back (cracked tank) and was able to find a tank for it (at Home Depot if memory serves). Of course my toilet wasn’t 30 years old, so YMMV.