wastewater and foulwater drains

[pp]

Hi

I wish to fit a water butt to collect rainwater from the roof but I have noticed that the bath and basin water from the bathroom discharge into a hopper that splits the downpipe from the roof. Consequently, the water butt will fill not only with rainwater from the roof but also bath and basin water from the bathroom. Surely this is not right? Would I be right in thinking that this is an illegal setup? I must mention that the toilet does not discharge into this pipe! Any advice would be helpful please.

Phil

[Andrew Gabriel]

It depends where you live if surface and foul drains are combined or separate.

[EricP]

How old is this pipework arrangement???

[Andy]

For a thirties house this is a standard arangement.

Andy

[auctions]

Quite normal. In many areas it all goes into the same system below ground anyway, so combining it higher up is fine, and was normal practice

If you want to divert the water, you could bend the downspouut across and run a second pipe parallel with the first down into the butt, then have the butt overflow connecting into the original.

A

[EricP]

It would make diverting the rain water to storage for grey use a bit easier I suppose.

[David Hansen]

On Sun, 04 Feb 2007 16:44:14 GMT someone who may be "pp" wrote this:-

You have described a traditional UK two-pipe (above ground) drainage system. What age is the property?

There is probably little wrong with the existing drainage as it is, however adding a water butt to it would be unwise.

The current setup? Unlikely.

What probably happens is that the rain water, waste water and foul water all goes into one pipe below the ground. All normal for older properties.

What you may do depends on how keen you are to save water and how the house is laid out. One option is to separate the rain and waste pipes at high level. Rain water goes down the existing pipe, with water butt attached. Waste water goes from a new hopperhead down a new pipe into the gully. You may want to intercept some of the waste water for the garden.

[pp]

The house was built about 1975 I believe but it has been extended. None of our neighbours seem to have a similar arrangement.

Phil

[Colin Murphy]

If you can get access to the Rainwater pipe above the head that collects the waste water then you need a Rainwater diverter kit. This would allow you to collect water via a hose pipe for the rest of the fall to the water butt.

Is the pipework plastic or cast iron?

[Roger R]

Perhaps its time for some new guttering and separate down pipes where you could tap directly into the rainwater down pipe. Purpose made tap off adaptors are available. (I'm not following this suggestion as I'm retaining my cast iron gutters and pipes) Many water authorities offer a reduction on water rates if the roof water runs to a soak away rather than discharged into the drains.

Housing developments built after the war tend to have separate surface and foul water drain systems. New towns built after the war have completely separate drainage systems, but most older towns have mixed arrangements, with separate systems in the newer parts and combined in the prewar areas.

The advantage of the separate foul and surface sewers is that the rainfall water is discharged locally into a river or lake maintaining the natural flows and ground water levels. Also a summer storm is less likely to overload the foul system causing unpleasent flooding. The down side is that some people consider a street drain as a suitable place to dispose of their old engine oil/paint/thinners/creosote/garden pesticdes etc and this then emerges in the local water course.

Combined foul and surface drainage sewers usually have some kind of storm flood arrangement, for example an underground weir discharging any excess directly into the sea or river, the high flows at that time minimising any pollution problems.

Roger R

[Colin Murphy]

There are rainwater diverter kits available that you could cut into an existing stack.