To me there has always been a fundamental problem using water which is perfectly good to drink to flush a toilet. At my old apartment I could not put a brick in the cistern (no smutty jokes please) so I filled sealed plastic bags to achieve the same result. This reduces the amount of water used per flush which you can balance to get the optimal flush, water usage and retention. Where I live now the units are “sealed” and “water saving” but to be fair that is still saving drinking water. Just like the bag trick it was reducing the waste but not removing it.
Now water is a limited redsource - no it isn’t - clean drinking water is a limited resource - better - and it is a waste to just flush it away. Yes we can now using evaporation traps make clean drinking water quite easily but that is currently not on a large scale. So what about the water in our taps. It uses quite a lot of energy to get there. There is the treatment and storage, the transportation and pumping, etc, etc. In an ideal world you would capture rain and grey water (that is water from your bath and shower) and recycle that back into your toilet waste system. In fact you can do that but not in an apartment or not easily - is that true?
So let me tell you about what I do. You will probably judge me harshly and I can understand why you might. Firstly let me explain the kit required. It is a bucket. Ok that done how do I use the bucket?
Well for me it takes awhile for the hot water to come through the pipes to my shower. So the bucket sits under the shower and collects the water until the water gets warm. Now the water coming out the shower already has a water restrictor on it so reducing the amount available per minute (something you can get from UU for free).
That is not the whole story? I also, when required, use this water from the shower to water my plants by leaving them in the shower whilst waiting for the cold water to turn warm. But I can do more!
Let me explain by describing my bucket. You see I use a pouring mop bucket from Vileda (other buckets are available) it has a narrow elongated elliptical shape which not to be crass I can easily step over. Which means I can leave the bucket in the shower whilst I am having the shower and not really even notice it is there. Eeeeeeeeer I hear you say but really I am just capturing water that would go down the drain that is 99 % water possible 0.5 % soap and 0.5 % dirty old skin (made up numbers). I wouldn’t dream of drinking this water ever but I found that by the end of my shower I have a full bucket (over 10 litres) and that is enough to flush the toilet 3 times for me during a normal day. I could if I wasn’t being lazy go and read how much water I had captured off the bucket - but I am so I won’t.
You are now going to ask if I leave the water on continuously during my shower. No I try and keep it below the 4 minute running water rule by turning the shower on and off. I really am trying to be a minimal as I can without resorting to flannels and washing up bowls (old joke to do with the Yorkshire water shortage).
Have I tried to monitor the amount of water I use? No. I should do I should take meter readings for one week normal and one week efficient. I’ve also thought about getting an OpenEnergy setup to track the water flow and electricity usage but I’ve been scared off by the need to use a soldering iron. Well that and the fact that somehow I’ve lost two soldering irons and solder in the various moves from place to place over the years.