Introduction: Water Saving Toilet-Mounted Basin
Have you ever thought how wasteful it is to flush the loo with drinking water, when there's so much grey water being produced by our daily activities?
This easy project adds a basin directly to the top of your toilet's cistern, so that when you rinse your hands, brush your teeth, etc, the grey water flows straight into your cistern, making it easy to flush with grey water.
Only a few tools are needed, and the system is not destructive to any part of the toilet - you can switch back at any time.
Step 1: Things You'll Need
- Drill with hole-saw attachment
- Impact driver or screw driver
- 20mm spade-bit
- Mitre saw or hand saw
- Plumbers tape
- Shifting spanner
- (Optional) Belt sander
- (Optional) Drill-press
- (Possibly) hack saw or angle grinder
- A sheet of opaque perspex, larger than the top of your cistern
- A garden tap
- Hose clamps (2)
- Braided house connecter to fit the water outlet near your cistern (long enough to reach the tap. Ours is about 80cm)
- Basin waste attachment
- Plastic container or bowl, to fit the top of your cistern
- Wooden square pole
- 20mm dowel
- Long wood screw
- Large diameter metal washer
The material cost came in about $25
Step 2: Cut New Cistern Lid
- Place the cistern lid on the perspex sheet
- Trace around the lid with a pencil
- Cut along the line with the jigsaw. Cut slowly and carefully.
Remember to use eye protection and a mouth mask when cutting!
Step 3: Drill a Hole Through the Basin and Lid
- Place the plastic container on top of the lid you've cut. You may want to use a measuring tape to make sure they are centered.
- With a hole-saw attachment that matched the diameter of the waste-outlet, drill a hole through both the container and the lid. I drilled the pilot hole through both whilst they where on top of each other, then the larger hole separately. Make sure the drill bit and hole saw attachment don't damage the surface you're working on (consider drilling on a scrap piece of wood).
Note: it's worth looking how your flush mechanism works, and placing the waste outlet accordingly. Ours ended up getting in the way of the flushing mechanism, so we had to angle-grind it down a little.
Step 4: Attach Waste Outlet
- Push the waste outlet through the holes. A rubber washer came with the outlet, and we placed that on the very top of the thread, so that it sits in the basin.
- Tighten the screw well, so as to avoid leaks.
Step 5: Make the Tap Stalk
- Cut down the wooden square pole to the height you'd like you tap to stand.
- Using the spade-bit in a drill-press (or drill), drill a hole near the top of the wood.
- I also chose to sand the edges of the wood on the belt sander
- Cut the dowel to the length you'd like your tap to stand over the basin.
Attach the tap to the dowel with the hose-clamps
Insert the dowel into the hole you've drilled. Drive a woodscrew through the side to hold it in place.
Apply plumber's tape to the thread, and firmly attach the braided hose to the tap
Step 6: Attach Tap Stalk to the Lid
- Drill a hole in the lid where you'd like to mount the tap stalk
- With a washer in place, drive the long wood screw through the hole, and into the wooden stalk.
Step 7: Putting Everything Together
- Turn off the water outlet near the toilet
- Disconnect the existing braided hose from the cistern
- Using a bit of plumber's tape around the threads, attach the braided house to the water outlet. Use the shifting spanner to make sure it's tightly connected.
- Slowly turn the water outlet back on, making sure there are no leaks.
- You're done! Enjoy saving water!
Step 8: Improvements After Testing
- Some water creeped under the basin (not much at all). Applying silicone sealant near the waste outlet would solve this.
- The thread at the bottom of the waste outlet was quite long, and it got in the way of the waste mechanism. Placing the waste outlet to the side would've avoided this.
- If you have extra budget, you could use a shiny faucet that arches over into the basin instead of a garden tap on some wood
Thanks for following this instructable! I you have any suggestions, questions, or comments, please leave them in the comment section.
We have a be nice policy.
Please be positive and constructive.
If there could be a way of adding some sort of float indicator that lets someone see from the outside how much water is inside the cistern, that would be quite useful in knowing how much water is needed, and whether or not its time to add extra water, or time to...uh...
...take the dog for a walk?
...empty the tank?
....take a zizz?
....drop the kids off at the pool?
...sink a battleship?
...build a log cabin?
...go where the king goes alone?
If you use two or three screws the wooden stalk will not twist. Carl.
Excellent idea! How do you get the gray water into flow into the container?
How much more complex would it be, to take an existing sink from the bathroom, and mount it on top of the toilet? It would increase the available floor space in the bathroom quite a bit.
With a little bit of handiwork, I think it could be a good weekend project!
Since the sink would already have the drain, I guess one only need make the hole in the toilet lid. Is there a reason why you didn't drill through the original toilet lid? Is it difficult to drill though ceramic/porcelain?
The cistern normally fills till the float rises and toggles a switch to shut off the water. How do you make sure you have enough water to flush?
Hello! see my reply to the question below :)
So the idea is that the toilet tank doesn't fill on its own right? Since any water you add to a full tank would just drain away, and you disconnected the fill line. So you need to manually make sure there is enough water in the tank for it to flush, right? Perhaps some form of fill gauge would be helpful? I can imagine a few options, but not sure how useful they would be. How have you managed making sure it has enough water?
Correct - the toilet doesn't fill on its own. After a while of using it, I started to get a sense of when I had produced enough grey-water to flush. You're right, though - a gauge would be useful!