Re-using grey water with a hose and a siphon - bath system.
For the last six years or so I have been running an old hose from my bathroom (first floor) to the flower beds.
When not in use, I hang the hose/siphon from a hook outside the bathroom window. The hose then runs down behind the guttering and behind raised beds. It is permanently placed under big bushes. I can then reuse bath water or collected shower water in the tub. I put the hose into the tub with a little siphon/hand pump attached (£5 on Ebay). I squeeze the hand pump about eight times to get the air out and the water in, and then the water runs out through the hose on its own until the water is gone. Once things are running, I can then go down to the garden and move the hose outlet about, if I need to.
This system works well for me because the a) bathroom looks out right over the garden b) the bathroom is much higher than the garden so the forces clear the bath c) the window is right by the bath so it's simple to unhook the siphon and pop it in the bath without mess or leaks.
NB. The siphon pipe does need to be close to vertical for it work properly.
As long as the hose outlet is lower than the water source, physics will clear the bath etc for you. The hose can go below the level of the flower beds and up again.
It works wonderfully well for me and feels like a great, practical use of grey water. It's not a good idea to store grey water. There is ecoli etc in the water which gets stinky quickly. But it's fine on flower beds, if it's 'fresh'. Just put in the bath plug to collect shower water. The water pressure for me is good because the source is on the first floor. It would work just as well with a bucket or a sink.
You can run washing machine outlet pipes/hose out onto beds. Best to use eco/gentle soaps. Best not to run dishwashers this way as the use softeners/salt which is bad for plants. In both cases the machines would need to be at a point higher than the garden if you are using pure physics to empty the machines. (A sunken kitchen below the garden, like mine, wouldn't work).
I hope the detail might prove useful to you as ideas for reusing water.
Hooks where the hose and siphon pipe hang when not in use. The hose is tied in permanently behind the guttering, which disguises it. Kind of.
*The (green) hose runs behind the planters on the left and the outlet sits under rose bushes. I can then come down and move the hose end about, once the water flow is going, if needed.