A lot of people use their bathroom to get messy: that way, you can just send all the pie/gunge residue down the drain.

If all your waste water goes to the same place, that's easy enough. However, I've been reading up on ways to reduce your water consumption, e.g. using rain water rather than drinking water to flush your toilet or wash your clothes.

As I understand it, waste water can be classified as "grey" or "black". If it contains faeces then it's black, and that needs extra treatment by the water company. So, the waste pipe from your toilet is black, and so is the waste from your kitchen sink (in case anyone has put raw meat in there). On the other hand, waste water from the bath/shower is normally grey water, and that could be used in the same way as rain water (i.e. fed into the toilet cistern or washing machine).

So, my question: if you've just had a messy session, is that water grey or black? I don't think I'd want to re-use that water right away, but maybe it's easier to process than actual black water? Putting it another way, if you lived somewhere that classified each waste pipe, would you still feel comfortable using your bath/shower as a gunge tank, or would you want to gather up the mess at the end and flush it down the loo?

(Mods, feel free to move this to the off-topic forum, and apologies if I've posted it in the wrong place,)

Luckily where I live we have no shortage of water. In fact, the stuff literally just falls from the sky with quite a degree of regularity...

Which planet would that be?

Earth...

We have a bigger problem with flooding than drought and our water comes to us at less than a penny per gallon round these parts.

Current status of the USA

East Coast and South - Hurricanes, Nor Easters, flooding, tornados
West Coast - Perpetually on fire, the earth literally tries to eat you.

If you've had a messy session then it's not grey water. On that basis, waste from a messy session can only go with black water.

In this house I believe all the waste, including the gutters, from inside goes to the same "black" drain so in practice it doesn't matter which drain in goes down here, provided it does not block it. I suspect newest houses might be a little different and gutters often drain elsewhere these days.

The system you're referring to you'd definitely want it down your black water drain system. Putting it down the grey would mean having to change your filters very frequently AND could result in having to have your system purged because of nasty bacteria forming.

Sorry for the serious post, I'm pretty clued up in this area.

You have filters on your grey water disposal?

If I've understood the original post then yes. There should be a filter before it enters the main storage tank which prevents any unwanted particles getting into the tank. Things like leaves in the guttering, fluff from the washing machine, stuff you just don't want recirculated through the house or allowed to build up somewhere.

Obviously the filter isn't perfect but either way you don't want to block it up with the remnants of your recent WAM shoot lol!

Thanks Messy_Mr, that's useful.

Right now, I have 2 pipes running down the side of my house outside my bathroom. The toilet waste goes into one, while rain water and sink/bath waste go into the other. (I'm going to separate out the rain water so that it can go into a water butt.)

After a bit more reading, I think that trying to store/filter my own water tank is just asking for trouble. I don't know what happens to those pipes when they drop below ground level, but I assume that they go to separate places (or at least they could). So, if the water company is doing separate amounts of processing for grey/black water, would gunge still count as black?

I wonder what happens if someone has been out playing rugby, and they take a shower when they're covered in mud. Would that count as grey water?

Hmm Interesting. After forty years of camping and boating, the almost universal understanding of Black and Grey water is as follows. Black water is what emerges from the toilet including bodily fluids and matter. Grey water is what emerges from domestic washing and bathing. So if it goes down the bath it goes through the grey water channels. If you flush it down the toilet it follows the black water channels.

In fact in most of the UK (possibly all of it) this is an academic question as mostly they meet up before or just after leaving the house. The water companies rely on the high fluid content of grey water to flush out the sewers containing the black water components. I am talking about the cases where the house is connected to the mains sewer. Where there is a septic tank, then efforts are made to keep the two types of waste apart. This is simply to reduce the water content of the septic tank,so it does not need emptying too often.

When camping, often the most frequent disposal method for grey water is around the hedge roots at the sides of the field. In the vast majority of boating activities, the grey water is discharged directly into the river or canal. In France, although illegal, many boats also deal with black water in the same way. Indeed this used to be the case in Britain too.

When the waste appears at the water treatment works, there are indeed screens which remove solids which are then treated separately, the remainder is pumped into filtration beds where bugs digest the bad stuff, before being recycled into rivers and ultimately drinking water, so the whole process is repeated.

Sorry to be so pedantic, but your Rugger playing friend (and his friends too) are producing grey water when they bathe.