A $9 Gravity-fed Greywater System




If you have a bathtub or washing machine near a window that is up-slope from a patch of yard that needs water, you can greywater easily with a minimal investment from the hardware store and household items. 

NOTE: make sure you use earth-friendly cleaning products if you do this! There are a lot of good cleaners that use natural surfactants.

ALSO NOTE: In spite of this image, taken after a week of gardening and summer fun, employing greywater does NOT mean you must live in filth! (This pic was snapped just before I scrubbed with Bon Ami.) (I'm new at this.)

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Step 1: Buy a Hand-pump at the Hardware Store.

This is the $9 part. Ask for a hand pump, a suction pump, or a cheap plastic pump for about $5 at your local hardware store. Also purchase a few yards of hose that will fit on the end of the accordion-folded hose that comes attached to the pump.

Step 2: Close the Drain When You Take a Shower.

The first person in the shower each morning closes the drain, and we collect water from up to three showers, which can fill up the bathtub halfway (about 40 gallons, I think). The last person starts the pump, which we keep on a hook inside the shower window when not in use.

It typically takes 5-10 quick squeezes to get the pump flowing. You can adjust the suction with the little nozzle on top of the pump.

Used shower water is usually not very hot. I usually let a bath cool before emptying it with the pump, however.

Step 3: The Water Goes Out the Window.

Make sure you get enough vinyl tubing so the system ends BELOW the water level of the bottom of the bathtub.

Insert the vinyl tube into the male end of a garden hose that's long enough to take the water where you want it. (Garden hose not included in the $9 budget.)

Step 4: Secure the System Outside.

Although the inside part of the system can be moved around between showers, it's best to hook your hose to the wall outside. This close-up shows how I used two push-pins and a stray piece of wire. 

The vinyl tube stays in the window all summer, and can be brought inside after the season ends so you can close your window in winter.

The hoses get a little grungy on the inside over a year or two -- but it costs almost nothing to replace the whole system!

The first year we used this we cut our water bill in half!

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    8 Discussions

    Dream Dragon

    8 years ago on Introduction

    Hand pump? Shower? How about one of those funky foot operated pumps they use on boats, would probably put your materials bill up a bit, but it would be a nice option.

    2 replies
    cavenoidDream Dragon

    Reply 5 years ago on Introduction

    And have somewhere to put the foot pump when you're taking a bath... with this gizmo we just hang the thingy on the shower rod.

    Dream Dragoncavenoid

    Reply 5 years ago on Introduction

    Ya Daft 'Apeth!


    Foot pump goes outside the bath, hose from bath to pump, hose from pump to garden...

    Hang the hose over the shower rail if you like, but it's probably still more expensive than $9


    8 years ago on Introduction

    LOL, nice. Will there be photos on how best clean a tub? I need such photos to show me how...

    1 reply

    Reply 5 years ago on Introduction

    I think it has something to do with soap? Anyway, this system is a great way to keep your bathtub kind of grungy looking, since things drain slowly and never down...


    8 years ago on Introduction

    How difficult would it be for you to connect to the drain? I see the building s wood, but I don't know your plumbing.


    1 reply

    Reply 5 years ago on Introduction

    Not difficult, but costlier than $9. We'd like to create a diverting switch on the drain plug. I'll post pix when we spend the bigger bucks!


    5 years ago on Introduction

    The squeeze-pump gets the water started, but the main force at work here is that of a siphon. The outlet of the plastic tubing must be below the inlet in the tub - then the weight of water on the downhill side will draw water up and out of the tub: a siphon.