I saw a youtube video of how Japanese hotels conserve water in their bathrooms with toilet sinks.



The water which fills up the toilet tank for the next flush flows out of a faucet first, then into a basin where it drains into the tank. I thought this idea was so clever I came up with a similar design and installed it on our standard toilet.



The faucet is a Delta and the basin is a Japanese porcelain serving bowl. I used a diamond bit to drill the holes for the drain in the basin and toilet tank lid. Man, is porcelain HARD!

Clever idea but would it not pose a challenge (and an increased risk of falling) for a person who is elderly or physically challenged in some way? I would find it awkward to use. And as a person who hates housecleaning, why create more things to clean? Guess it's not for my house. But it's fine for others who like it.

Personally I choose other options for water saving that would save a lot more water volume, such as seldom using the toilet in the first place (preferring other non-water options), taking very short showers and diverting that water to a banana patch, cycling my laundry rinse water back to the machine to be used for the next batch of wash, etc. My problem is that I'm a K.I.S.S. sort of personality. While that toilet/sink works, it's not simple enough to appeal to my mentality. Now....I had a brother who loved intricate things. He probably would have thought it was really cool, though his wife would have hated cleaning it.

Greg, I really, really like your DIY approach! Rather than pay top dollar for an innovative toilet/sink, you came up with a neat solution. Pretty clever!! You've earned an apple for that. 😀

Yes, I've used those types of set-ups in Japan in a Pension (Guesthouse). They're normally reserved for a small toilet cubicle as a space saving idea. They call those types of toilet rooms a 'Night Toilet' - as the name implies, it's only meant to be used if you wake up at night and need to go. In typical Japanese fashion, there's a proper facility elsewhere that's used during the day.

The challenge with those types of toilets is being able to wash hands quickly enough before the water switches off!

Hey, I had those when I lived in Japan! I thought they were great. The ones I had had a much smaller faucet and a thinner stream, like a water bubbler, so there was no hurry to wash your hands, it took quite a while for the tank to fill.

Su Ba wrote:Personally I choose other options for water saving that would save a lot more water volume...

So did we. I had installed the toilet sink before designing our sewage treatment plant. This rendered the toilet sink a novelty as our black water system recovers all of the water from our raw sewage.

That's really neat! When I read the thread title I thought this would be a sink people pee in.

James Freyr wrote:That's really neat! When I read the thread title I thought this would be a sink people pee in.

Well... you could if you stood on the toilet seat. (lol)

Greg Mamishian wrote:

Well... you could if you stood on the toilet seat. (lol)

Oh man! Every once in a while I read something that just makes me belly laugh. Dude that was funny!

Trying to get my in-laws to install one.  They have what I affectionately call a "pee closet" (a closet with a toilet in, next to the bedroom).  The sink is downstairs.  I don't like not being able to clean my hands in the same room, and saw these in Japan.  Home Depot in the USA carries a unit that will fit standard toilet tanks, but not in Canada.

https://www.homedepot.com/p/SINKTWICE-Toilet-Tank-Cover-Faucet-and-Sink-Combo-in-White-1317/301276506

A urinal is pretty much sink you pee in...
When I was young I visited my older sister in NYC.
She was living in a  squat in the lower east side.
They had electric, and running water,  but no plumbing or carpentry skills, so they flushed the toilet in the middle if the room, with a bucket filled at the sink.
I didn't have nerve to suggest I could skip a step...

A sink set low enough to pee into, with a second sink set up high,  to drain into the first, and everything  draining from there into a mulch basin, would be a nice addition to a camp grounds.

It's really not a good idea to use greywater in this way.  You should never store greywater in a tank for any amount of time.  If you end up using the sink a few times per day and not using the toilet, or say you wash your hands then leave for a weekend, you will come back to foul, sinky water in the tank and possibly pathogens.  The rule for greywater is simple -- put it outside, right away, on the surface of the ground.  Never store, never pump, never hide.

David Balt wrote:It's really not a good idea to use greywater in this way.  You should never store greywater in a tank for any amount of time.  If you end up using the sink a few times per day and not using the toilet, or say you wash your hands then leave for a weekend, you will come back to foul, sinky water in the tank and possibly pathogens.  The rule for greywater is simple -- put it outside, right away, on the surface of the ground.  Never store, never pump, never hide.

You can store your grey water indefinitely simply by adding a small aerator to keep it from turning foul.



If it's under 100 gallons, a small aquarium air pump like this one will work fine.



We aerate all of our household raw sewage.





The risers are always open with just a metal safety grids on them because there's no smell.

Once the blackwater has been aerated settled filtered and pumped up to the storage tank it will not turn foul again.

What kind of regulations did you have to contend with in constructing this system? And do you get hard freezes where you are located?  I'm guessing not in CA?

David Balt wrote:What kind of regulations did you have to contend with in constructing this system? And do you get hard freezes where you are located?  I'm guessing not in CA?

We get some Winter freezing, however with hot water from showers, washing dishes, and from the washing machine flowing into in the underground tank, it always stays well above freezing. Warm water is constantly being pumped into the green above ground storage tank where it gets used, so it doesn't freeze.

All of the houses here have their own septic systems. Government acts upon complaint and since there are no foul odors there's nothing for anyone to complain about. We've used our blackwarter system for three and a half years with absolutely no problems. It's literally saved us thousands of dollars on our water bills.