I recently bought a two-in-one washer dryer combo that needs to purge water somewhere. Some people use a bucket, others use their bathtub, and some use their sinks or toilets. I have read mixed opinions about whether draining the water into the toilet is a good idea.

To verify some of the information I have read online I have performed a series of tests to see if my toilet could handle a flow of water.

#Test 1 (Toilet Bowl) For this test I wanted to see what kind of volume of water the bowl could handle. I did two tests with varying rates of water flow. If I simply dumped a large bucket of water into the bowl there is enough pressure from the weight of the water for the toilet to actually flush itself (without using the handle). This seemed normal to me.

#Test 2 (Toilet Bowl) Instead of dumping a large volume of water into the bowl all at once, I decided to dump the bucket of water into the bowl, this time letting water trickle into bowl slowly at an even pace. The result was that the water level in the toilet bowl never really changed.

#Test 3 (Toilet Tank) In this test I simply poured water at an even rate into the tank while ensuring that the tank did no overflow. There is about 2.5 inches of free space between the water level in the tank, and the edge of the tank. The overflow valve in this experiment did a great job of keeping the tank evacuated of excess water.

So the result of all these tests were that my toilet, either tank or bowl, seem to be able to accommodate a stead intake of water. Since my washer/dryer combo hasn't been delivered yet I don't know the exact rate of water expulsion or volume of water, but my assumption is that it would not exceed that of the bucket of water I did the tests with.

The one thing I did not account for in all of these tests is suds. I have heard some users mentioning this, but can't imagine how they might slow things down. Any insights on this would be useful.

So my question is this; which is better, tank or bowl? I would prefer to have the water drain out into something that isn't visible so creating a custom tank lid with a hole for the outtake hose of the washer/dryer is something I am considering.

The washer/dryer combo I bought is the GE 24-inch 2.4 cu. ft.Capacity Front Load Washer/Condenser Dryer Combo.

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    Your toilet tank is designed to only handle clean water. The mechanism typically includes some mix of plastic, rubber and metal. Anything other than clean, cold, water - e.g., suds, dirt, etc. - is not a good idea. The bowl is a different story altogether - it can handle "anything" as it has no moving parts, so it becomes a question of whether it can handle the typical rate of output or not. Aug 3, 2023 at 22:35
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    @manassehkatz-Moving2Codidact greywater flush systems exist, and that's the least treated use of greywater. It doesn't require special toilets (at least with wash-down flush). One that's simple and interesting is a Japanese thing: on top of the tank is a washbasin. After you flush, the water to refill the tank comes out of the basin tap for you to wash your hands. The now-soapy water fills the tank for the next flush
    – Chris H
    Aug 4, 2023 at 7:21

1 Answer 1


I think that draining the washer into the toilet is an odd option. If you own, pay a bit (or DIY) an actual washer drain right next to the washer water supply. If you rent, you're going to be on the hook for any sort of flooding caused if this should happen to overflow.

If you do choose to drain into the toilet, be aware that most washing machines pump water out pretty quickly, so your slow, even pour tests are irrelevant. You would want to dump it into the bowl, since the large influx of water from the tank is what makes the flush happen anyway (that's what the flush handle does - rapidly empties the tank into the bowl, then physics takes over).

I'm not sure how big a bucket you used, but you'll want to make sure that you pour as much water from buckets as the maximum amount of water used in a maximum size load in your washer.

Soap suds won't necessarily slow down the rate of flow, but because they're, well... sudsy, they may overflow the bowl and run down onto the floor, even if the vast majority of the actual water manages to go down the drain.

All in all, I'd be very skeptical of this working out well, but it is your place, so go for it if you want. Just don't expect exceptional results, especially if you plumb it into the tank.

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    Machine washing detergent is deliberately low foaming. If it wasn't, it would form suds in the machine, and escape through the detergent drawer (of a front loader). If you've ever used hand wash detergent in a machine by mistake, you'll have seen the difference
    – Chris H
    Aug 4, 2023 at 7:23

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