Would you buy or install this if it was made available?

[A580Hojas]

If your WC and hand basin are quite close to each other in the bathroom, what would you think of a system that diverted the water you have used to wash your hands or brush your teeth with into the toilet cistern. Via a pipe that feeds from the sink outlet into the cistern - it might have to be slightly visible because burying it in the wall is just asking for problems if there is a leak at some point.

But it would mean that the toilet is flushed using slightly "grey" water rather than 100% fresh clean water every time.

We have one of these in our tiny downstairs WC: www.victorianplumbing.co.uk/seattle-combined-two-in-one-wash-basin-toilet?campaign=googlebase&pagetype=shopping&gclid=CjwKCAjwzNOaBhAcEiwAD7Tb6CCTVxcQfWBAdCQzFf0s313LLESeQCvVYqvWuWDHhepVgQI2PN-yThoCA6QQAvD_BwE&gclsrc=aw.ds

I’m guessing the issue with making them for larger spaces is the connecting pipe needed which many people would think unsightly.

I would, OP but I don't really care how things look when they're better for the environment. I hope that'll be the norm for most people soon.

Good idea. Would there be enough water from hand washing to flush a toilet?

It already exists. PIL have this.

Sorry OP it’s as @ComtesseDeSpair description not yours.

I’m more concerned about the amount of water wasted by water companies.

Lots of the toilets in Japan are like this.

Yes, I've seen those combined toilets. But you wouldn't really fancy leaning your face over it to wash your face, or brush your teeth in it?

I could put up with a snake pipe showing for the environmental and cost benefits (if you are on a water meter which most are now). The pipework would be below the basin of the hand basin I imagine. Was just wondering if anyone else would.

My PIL also have one. No issues at all with it, but like PP says it only really works in a tiny space.

I'd like all newbuilds to have grey water (from basin, bath/shower and kitchen sink) harvested as standard and stored in a tank, and toilets plumbed to fill from this tank. And then, for houses that have already been built, a kit that could be retrofitted to do a similar job as you have suggested.

I have a basin/toilet combo like the one above.

The flush water doesn't look any different.

It's very sensible and I don't know why it isn't standard practice

I couldn't in my current bathroom, but if refitting a bathroom I wouldn't mind.

Just to be 100% clear - I know that the combined toilet/basins exist. I'm thinking of a set up that could be installed without ripping out and dumping existing toilets and basins.

I absolutely would.

Needs some thought- how does the waste water get diverted if the cistern is already full - don't want it coming out the overflow pipe regularly and so on.

I think the setup you are describing wiuld require a pump to get the water into the cistern. I also suspect the oral bacteria from the teeth brushing would create a horrible slimy biofilm in the cistern if you went away and didn’t flush the loo for a couple of days.

Ah yes, the pump thing . You can't make water travel upwards. Or can you??

This. I recall the instructions with our unit advised only to hand wash in it using soap, otherwise the cistern and toilet bowl basically become a bacterial soup mixed with organic and inorganic particles. Unless it's filtered, sterilised and kept in aseptic conditions you'll end up with a stinking mess that blocks the valves and sits festering in the bowl. Rainwater harvesting for toilets is an alternative but difficult enough with current regulations in the UK.

Of course, who wouldn't? It's completely ridiculous that we flush our toilets with clean drinking water instead of grey or rainwater.

Surely it would be easy to fit in new builds as standard. I know a few businesses that work like this, but they're forest parks and ecological research places.

We have this too

Ah yes, the pump thing Sad. You can't make water travel upwards. Or can you??

Perhaps some sort of Archimedes screw, operated by turning the tap? Or the act of pushing the toilet flush lever down would operate a vacuum pump that would draw water up into the cistern?

Systems like that are very common in Japan, I quite like them and wish they were more common elsewhere in the world, even in larger bathrooms where space isn't an issue, it's a good way to save water

You'd need to consider what kind of toilet it's being installed into as well. For example high cistern would need the pump, all would need to have an overflow into the toilet rather than an external overflow.

Wouldn't a gravity fed system for upstairs sinks to fill downstairs toilets make more sense?

I suppose either rain water or bath/shower water would be the best rather than handbasin water.

Our previous house was a new build that had a tank under the drive that fed the toilets and garden tap. Should be obligatory for new houses I think.

Given how disgusting the mess is after teeth brushing, I wouldn’t want it to be the only sink.