Grey water

[undyingking]

Has anyone got experience of, or knowledge about, collecting grey water for garden use?

My current plan is to attach a water butt to the external downpipe from our shower, like the one that collects rainwater on the guttering downpipe. What do I need to consider?

For example, does gribble collect in the butt, that might need clearing out or treatment? What's the pH of the collected water going to be like? Do you need to let it stand before using it on the garden? And other such things that I haven't thought of.

Comments

[hatmandu.livejournal.com]

No experience, but you might find some info here from recent Guardian useful (scroll down, esp. to bit about reservations).

[undyingking.livejournal.com]

Mm, interesting, thanks!

[karohemd.livejournal.com]

I personally wouldn't do this without some sort of filtering system as I don't think soap and tensides are good for plants (or the groundwater).

[undyingking.livejournal.com]

Tensides ?

Same thing as surfactants I guess? I don't know much about this area of chemistry...

[karohemd.livejournal.com]

Er, yes, indeed, sorry. Didn't realise it wasn't the same usage in English. In fact, "tenside" doesn't seem to be used but wikipedia redirects you to surfactant when you enter tenside.
Made sense, though, tenside is related to tension so I didn't even think it would be different. I do know surfactant, though but my brain didn't get that far. ;o)

[chrisvenus]

Yeah... I was wondering about soap on plants being a good idea...

[undyingking.livejournal.com]

Spraying dilute washing-up liquid on plants is the standard way of keeping down greenfly. But we use Ecover for that... I don't know if my shampoo etc is bio-safe like that.

[bateleur.livejournal.com]

Although in fact detergents are harmful to all insects since they cause dehydration by stripping their waterproofing. (At least that's my understanding of how it works, but IANAE^[1].)

---

[1] Where 'E' = Entomologist.

[undyingking.livejournal.com]

That's my understanding too. The theory is, I think, that aphids will be the only things actually on the plants as you spray them, and the detergent'll break down before any other insects meet it. But whether that would be as safe when you're actually watering the base of the plant with it rather than just misting the leaves, I'm not so sure. Dilution levels must be a factor too, I suppose.

[a-llusive.livejournal.com]

I've read elsewhere that detergent isn't such a good idea, so abandoned using it. They suggested its the vigorous water of the spray that is of help rather than the detergent anyway.

I'd suggest an arrangement with an accessible valve so that when you clean the shower more aggressive cleaning chemicals go out the 'old' way and you only have to consider regular toiletries which are probably adetergent-level problem, depending on your plants.

[undyingking.livejournal.com]

Mm, that could work, it could just be a valve on the downpipe diverter.

[fractalgeek.livejournal.com]

I don't believe that most human-safe chemicals are a big problem for MOST plants - if you would normally use tap water on them.

The usual rig I have seen is a T overflow on a gutter downpipe, which helps to take anything that floats to the top off.

I'm definitely interested in your results, as we want to something similar, and get the downstairs toilet fed from a (new) upstairs bathroom.

[undyingking.livejournal.com]

a T overflow

Mm, that's what I was planning, good.

get the downstairs toilet fed from a (new) upstairs bathroom

That's a great idea, seems the ideal use for it. Will have to remember that if we ever get a downstairs toilet.

[mrsdanvers63.livejournal.com]

My neighbour two doors down siphons bath water into a water butt for use on her garden; straight out of the bath, out the juliet window and into the butt.
As for it's efficacy - her garden flourishes.

I think the impact of any chemicals would be mitigated by surrounding gardens in an urban situation. My neighbour uses chemicals; I don't. Birds and insects flourish in my garden and pollinate hers.

[undyingking.livejournal.com]

We generally don't use chemicals in the garden, so it seems a shame to compromise that with our grey water. Although maybe saving the water is more important. Difficult to evaluate some of this eco stuff!

My hope was that someone would post here saying something like "That's OK, sitting in the butt for a few days will allow all the harmful chemicals to break down / settle / etc, or you can put barley straw or something in the butt that will have the same effect" but no joy yet...

[sea-of-flame.livejournal.com]

I wonder whether you could get around the chemicals problem by switching to more ecofriendly in the bathroom (I would guess there are such products Out There, but can't offer any recommendations) - even so, you might want to consider whether anything cunning could be done in terms of choosing/directing outflow so that when chemicals DID need to go down, you could direct them straight to the conventional drain rather than the tank.

I suppose it's far too simplistic to consider two plugholes & a movable plug in the shower base...? (Over-simplistic in the sense that well, of course it would *work*, and be easy to manage when in the shower, which is the critical thing - but I bet most shower bases aren't designed with such a thing in mind, so the execution would be Bloody Awkward and involve tryin to drill big holes & make sure everythin was plumbed in in a non-leaky, building-standards-compliant fashion!)

[undyingking.livejournal.com]

Mm, I'm not sure it would be safe to drill another hole in the shower tray, from the point of view of structural integrity -- it's made of a fibreglass-resin compound and has all sorts of cast-in bracing and ribs underneath around the existing plughole, to allow its structure to sustain the weight required. Plus we'd have to take the whole bathroom floor up to lay the extra waste pipe.

I've always been worried about shower cleaning chemicals and toiletries damaging plants.

[a-llusive.livejournal.com]

That's why I use rainwater but not greywater.