Update: I've done it!... and it works.

sketch of situation

How can I pump this unclean water from our 2nd floor to 1st floor down to our drainage?

I keep accumulating a lot of water (enough to fill a water basin) every 2 days from washing stuff.

I'm thinking of using some kind of Hose to transfer it. I've heard of 'Siphon' method, but to do that, I have to go to 1st floor and suck the hose a bit, which I don't want to. The water is unclean.

I don't even know if 'siphon' will work in a 15 foot hose.

Or maybe use water pump. But I'm not sure what pump will I need. Are there any cheap water pumps out there that cost only around $10? water pumps that I see are a bit expensive.

Shrunk version of image from google drive link

  • 2
    Siphon will definitely work over 15'. I have used it to empty my waterbutt through a 50' hose. If you are really careful, you can suck the water over the windowsill and down below floor level of the second floor, at that point you can stop sucking (9' before the water reaches your mouth). This will be easier with a clear hose. The tricky bit is siphoning out all the water from the bowl. Commented Jan 13, 2020 at 10:49
  • 5
    More typically one simply drills holes in the floor and let gravity do the work, but this may not be an option if you rent rather than own the building...
    – Ecnerwal
    Commented Jan 13, 2020 at 14:19
  • 1
    Is it possible to raise the basin to the level of the window? What about putting holes in the floor or wall (finishing them to look neat)?
    – JimmyJames
    Commented Jan 13, 2020 at 18:30
  • 12
    How many years do you plan to have this setup? Can you stop using the upstairs water until a proper solution can be achieved? It may help you to disclose why you are in this situation in the first place.
    – MonkeyZeus
    Commented Jan 13, 2020 at 18:37
  • 16
    All this talk about siphoning and pumping seems like a massive XY problem. It's unclear where the OP lives, but how did this situation occur in the first place, why is there not plumbing to properly deal with this? Commented Jan 13, 2020 at 22:50

10 Answers 10


You can find a manual siphon pump at any large hardware or automotive store. It will look like a hand-sized rubber bulb, or possibly like a small hand-operated bike pump, with a hose on each end.

enter image description here

An arrow or other marker will be present on the bulb to show you which side is the intake and which side is the outlet. You simply submerge the end of the intake hose, put the end of the outlet hose at some lower point (in your case, out the window), and repeatedly squeeze the pump until it has pulled water up to and through the pump and water is flowing freely. Once the flow is established it will siphon out all the water (until the water height is equalized, which won't happen in your situation).

  • 1
    A homebrew or winemaking supply is yet another possible source for an "autosiphon" (no mouth contact needed. Will look different.)
    – Ecnerwal
    Commented Jan 13, 2020 at 14:21
  • @Ecnerwal Good point. But autosiphons are more expensive and (IME) harder to find.
    – Sneftel
    Commented Jan 13, 2020 at 14:26

A method that will work in your case is to coil up the entire hose in the water to be removed or ensure that the hose is completely filled by filling one end from the faucet until the other ceases to eject air bubbles. Once filled, hold your finger/thumb over the hose end and drop it out the window(?) which will start the autosiphon action.

If you have an outside faucet, you can also with the assistance of another person fill the hose from below. When the flow reaches the upper basin, disconnect the bottom and the siphon will begin.

To avoid backflow concerns, the down-gravity person will fill the hose while the up-gravity person keeps the end free of the dirty water. When the up-gravity person indicates that there is a full hose, the down-gravity person can turn off the faucet/spigot/tap and the up-gravity person will immerse the end in the basin.

When the down-gravity person removes the hose from the tap, siphon begins.

  • Always great to meet another Pogo fan.
    – user109695
    Commented Jan 13, 2020 at 14:40
  • Clever second suggestion - rather than using an upstairs pump to directly empty the basin, use a pump/pressurized water source downstairs to slightly fill the basin, and then let gravity do the rest. Commented Jan 13, 2020 at 20:17
  • 5
    Gravity: It's not just a good idea; it's the law.
    – fred_dot_u
    Commented Jan 13, 2020 at 20:18
  • Does using the downstairs hose faucet present the opportunity for backflow to feed dirty water back into the clean water supply? Commented Jan 13, 2020 at 20:36
  • added info to answer.
    – fred_dot_u
    Commented Jan 13, 2020 at 20:43

Wanted to add a clarification to the auto-siphon technique - you do not need to fill up the entire hose. You only need to fill up enough to make it without air gaps to a level below your siphon source, e.g. the medium-blue in my poor drawing below. If you have a 20 foot hose this means you can just coil up the first 4-5 feet in the dirty water so it is totally filled, plug that end (perhaps with your thumb or a bend to prevent fast leaks, and then toss as much as possible out.

siphon diagram


If you want to avoid having to restart the siphon periodically, a useful trick may be to shape the hose into a sort of "S" shape, with the inside end extending to near the bottom of the tub, and the outside end going down but then rising to an altitude which is above the altitude of the inside end. The siphon, once established, will remain unbroken as long as the lowest parts of each end remain submerged, but will only transport water whose altitude is above the outside end. I've used this technique to handle the water dripping from an air conditioner, and setting the siphon up once at the start of the summer was adequate to carry water for the entire season.

A way of starting such a siphon without a pump is to immerse the entire hose in the tub, cap the outside end, move the hose to to where you want it while leaving the other end immersed, and then uncap the outside end. This may not be the most convenient thing in the world, but if you set the heights of things properly you shouldn't need to do it very often.

  • Good idea. It may be easier to fill it from outside with a garden hose. Commented Jan 14, 2020 at 10:31
  • @EsbenSkovPedersen: As I envision it, the outlet of the siphon would be far enough off the ground that filling it with a hose might be difficult. The key point, though, is that this sort of siphon will maintain itself unless so little water flows into the system that evaporation reduces the water level below the top of the outside bend, allowing air to enter the system.
    – supercat
    Commented Jan 14, 2020 at 15:48
  • Yes - it is more clear now. If for some reason they wish to have the end of the hose near the ground, that can be accomplished by adding an air hole to the hose where your setup would end, and for filling that air hole can be plugged with a thumb while filling from the bottom with a hose. Commented Jan 14, 2020 at 20:10
  • @EsbenSkovPedersen: It's important, though, that before reaching the hole the hose must go down to a lower elevation and then back up so that air won't be able to flow through the hole to reach the top of the siphon.
    – supercat
    Commented Jan 14, 2020 at 20:38

Siphoning will work, and how hard it is has little to do with how long the hose is going DOWN, its the distance from the top of the liquid to the highest point of the hose. (before someone very exact corrects me, yes, the longer the hose, the more the suction you create can cause the hose to dilate, reducing the effectiveness of your sucking action, but let's move on). Once the water reaches the apex, it starts to go down, and then creates its own vacuum.

Having 15 feet actually gives you a lot of time to remove your mouth before the water reaches you. As soon as you feel the suction start to release, let go.

but other commenters have given some very good, and inexpensive ideas for doing this without the old fashion mouth-siphoning method, so try those.


Install a sink above the 3' height

The root of your problem is that your wash water is on the floor. Most people with sinks have the sink at some height above the floor. And I have a feeling you, too, work with the water at some height rather than stooping, and then place it on the floor.

Well, don't. Treat the altitude of the water as a precious commodity, and rearrange your water use (e.g. With a sink) so the water finishes at 3' high. Now, it gravity feeds.


A small submersible sump pump should be sufficient to get a syphon action moving and can be made automatic with a float On/Off switch.

enter image description here
     Basic operation of a Sump Pump

The end of the discharge pipe can be higher than the 'unclean water' depending on the efficiency of the pump but it can always be lower providing that the pump is sufficient to raise the discard water 'over the top' of the highest point of the water's path. Once that occurs, water always flows downhill.

enter image description here

  • You might also consider a small marine 'bilge pump' as an alternative to a conventional home product.
    – user109695
    Commented Jan 13, 2020 at 14:36
  • I'm a little confused by the pictures. The sump pump shown in the image will not siphon after it's stopped, since the outlet is higher than the inlet. In the aqueduct picture, there's again no siphon action, as there's no point where the water has to go "up and over" an obstacle. The inclusion of the vents actually make it quite the opposite - if the water stops flowing upstream, the inverted siphon will remain filled with water, and not get siphoned dry like it would without the vents - this is how a P-trap in your plumbing works, which must remain filled with water at all times. Commented Jan 13, 2020 at 20:26
  • Since its unclean water - filtration before the pump might be a good idea to stop clogs.
    – Criggie
    Commented Jan 14, 2020 at 7:33
  • @Criggie If the cost of a pump is already too much, I strongly suspect filters are not going to be used.
    – Mast
    Commented Jan 14, 2020 at 14:12

I would recommend using a siphon as it is uses no electricity. You can use a siphon pump or use some other techniques, for example you can pre-fill the hose before submerging it.

Otherwise use an "aquarium pump", they are much cheaper and will be adequate for the amount of water you are dealing with. Try getting the highest wattage within your budget, I reckon that 15-20w should be good enough.

enter image description here

  • 1
    I was going to post this if you hadn't beaten me to it! :) I've got an old aquarium pump I bought second hand for only a few bucks. It's great, especially when a siphon won't work (for whatever reason). Commented Jan 16, 2020 at 3:03

Low tech but you put a hose outside and a funnel in the top and just pour the water down it as needed?


Auto-siphon. The end of the pipe sits on the bottom of the tank, so it siphons right to the bottom dregs.

But what makes the auto-siphon work, is the rim of the bowl/tank must be higher than the bend in the hose/pipe. So tall narrow tanks are good. It also unfortunate means the pipe goes through the wall of the tank (since tank top is higher than highest point in pipe).

When the tank fills things go as normal until water hits pipe. Pipe fills as tank fills - so bottom end at first floor MUST be able to release atmosphere to let pipe fill. When water level in tank reaches pipe highest point, the the water in the pipe tries to rise with tank level, but can't as it flows into down section and drops away. The gravity pull on the water going down the pipe, exerts lower pressure effect on water in pipe, sucking the water out of the tank, and this will keep going as long as there is more water falling and stopping gas backflow in downwards pipe, than there is on the intake side of the pipe.

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