Did I really solve two problems with one solution?

Ever since we moved into our house (1950s ranch on slab) six years ago, the dishwasher has backed up into the kitchen sink whenever it drains. There’s probably at least a quart that backs up every time. Twice we’ve had to have a plumber snake out the main line for unrelated clogs. But both times this also took care of the back ups for a while, but the issue eventually came back. We've long since learned to live with it.

At the same time, we’ve had fairly regular problems with both of our toilets backing up. It eventually got so bad that about six weeks ago I got smart and finally replaced both toilets with Toto Drakes. Problem solved.

But here’s the crazy thing: Ever since I replaced the toilets, the amount of dishwasher water that drains into the kitchen sink has been slowly decreasing and now there’s almost no back up.

Did I somehow kill two problems with one solution? If so, how? I never would have thought the two were related.
Thanks

I'm guessing no. You probably have roots growing into your main sewer lin3 and the drakes may have produced enough "pressure" to blow the nasty bits off the roots but it will only come back sooner than later.

NO!!! Which sink did the dishwasher back up into? The one with the disposer or both of them. If just the disposer the problem is in the drain line between the disposer and the other sink. If both, then it is in the pipe from the sink to the main drain. NEITHER of these would be cured by replacing the toilets.

Thanks for the responses. I get the feeling this was an even stupider question that I thought. It was just such a crazy coincidence.

HJ: Ahh, there is no disposer. I didn't mention one. The dishwasher drains into the kitchen sink, which is right next to it.

Would have to see how you connected the DW to the drain. Being pumped, it must be done right, or gravity isn't enough to get it to flow where you want right away.

By "kitchen sink" do you mean a single bowl sink? If so the problem is somewhere between the dishwasher's connection and the main drain line.

hj said:

NO!!! Which sink did the dishwasher back up into? The one with the disposer or both of them. If just the disposer the problem is in the drain line between the disposer and the other sink. If both, then it is in the pipe from the sink to the main drain. NEITHER of these would be cured by replacing the toilets.

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Sound response answer right here.