How can I improve my greywater system?

We’ve had an email from Su:

I do like to tax the minds of all who read these sites, not intentionally, but in a ‘why don’t I know how to do that’ sort of way.

Here goes, I collect all the water from my washing machine, and use it to flush the loo. However, hauling watering cans of water up the stairs with a frozen shoulder is not especially easy. So I would like to construct (if possible) some sort of pump, preferably from reused bits. Unfortunately, I have not the remotest idea where to start!

I can easily put a pipe out of the bathroom window into the container of water, but it would be easiest if the pump, or at least the switch was at the ‘top’ end, so that I don’t end up running up and down stairs to switch it on and off. Would a washing machine pump (not that I have one lying around) do the job? Could it be solar powered?

All ideas gratefully received.

I haven’t had much experience with setting up greywater systems so I can’t really advice – hopefully someone else will be in a better position to comment. As someone who has an incredibly vertical house, I’d love to learn more about options for pumping water too.

One thing I will say though is could you change it around so you don’t need to pump upwards? For example, using greywater from shower/bath for the toilet, and using the stuff from the washing machine elsewhere (such as on the garden, if it’s chemical free). It obviously depends on the set up of your home – there might not be storage room on that level for the water – but it might be easier to rejig things that way then get a powered pump working.

Any ideas, suggestions or advice?

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8 Responses to “How can I improve my greywater system?”

  1. It would be nice if housing could be designed with this consideration in mind from the outset (for example a basement toilet ?)

  2. Robert Campbell says:

    I’m an engineer and I have thought about this. I’m in the USA so it is in that context but should work as well in the UK.

    Change the shower and washing machine drain pipes to collect the water in a plastic barrel. The barrel should have an overflow so it will drain to the sewer when full. There should also be a drain at the bottom so any sediment can be drained from time to time.

    Get a small pump of the type that is used in recreational vehicles, sometimes called “demand pumps”. They are availabe with an internal control to pump when the faucet is opened. They don’t need a pressure tank. I bought one at in the US. You should get one that operates at MAINS voltage.

    Connect the inlet of the pump a few inches above the bottom of the barrel so it will not pump sediment.

    Connect the pump to a line that supplies all of the loos and the garden spigot. Then, whenever the loo tank calls for water, or you open the faucet to want to water the garden, the pump will start and deliver water.

    Depending on how much you pay for water and sewer charges, the system should pay for itself in a couple of years.

  3. I contemplated recycling greywater, but ended up collecting rainwater and recycling. I designed the system very similar to what Rober says (above?). The main things to keep in mind are the pump – ie. you need the right one, and also the float switches. I got some great float switches for really cheap on ebay (from china – not brilliantly green I know!!). I made a bit of a mistake and presumed I needed a submersible pump which are a bit more expensive than normal pumps – but hey ho!

  4. PS: I calculated that I could pump about 400litres for the price of a normal UK litre of water via the mains.

  5. Trudy says:

    I have an ancient greywater system for my kitchen sink–concrete catch basin, like a mini septic, and several feet of holey pipe going out into the yard. I’m on many acres, so it can handle the effluent. The tank really should be replaced, as it is cracked in several places. I cannot get a new one. The local code does not allow this system any longer, but I can repair it or replace it as it is not a ‘sanitary’ system. But, no plumber around here has the components. All I’ve been able to find are commercial units. It’s for a small, <1400 sq ft house. I've made repairs with hydraulic concrete, but does anyone know where I can get a new tank? I'm in Alabama. Thanks.

    • Robert Campbell says:


      Unless the tank is where leaks cause a problem (such as near a basement wall) I would not replace it. The leaks into the soil are no different than the drainage out of the holey pipe.

      In Alabama there shouldn’t be a problem with freezing ground so it probably won’t get worse. You could probably find a small tank somewhere but the greatest expense would be installing it (digging the hole and connecting the pipes.

      Repairs should be done from the inside when the tank is drained. I have been in a few tanks with 16 to 18″ manholes, but you should do that only with someone around to help you out if necessary. Also, the tank should be vented. I use a window fan covering half of the manhole.

      If you can get it dried out you should be able to line the inside with a membrane of some kind such as rubber roofing. It is also possible to find roofing cement that is suitable for application when the surface is wet.

  6. Anni says:

    Why not use the graywater to start the next load of laundry? The rinse water becomes the next wash water. Then you can keep it right in the same room!

  7. Nyge says:

    Why bother with grey water – it is far better to have a shallow well as this would also supply garden water. As for a pump the type used to power a garden hose from a water butt would be fine … it maybe that you would need a two stage system to deal with the height to the upper loo.
    As for the well hollow it out using an extended post boring tool and line with concrete. It would take a few weeks to get clean water but it would then work. It might be that you need to pump to a storage tank at ground level using a timer on your pump.
    Grey water is awful so best put this down the sewer – it could be a health hazard … well water could be kept cleaner by using loo blocks in the storage tank.
    I gave up with rainwater / grey water years ago !

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