rainwater diverter

Funny enough, exactly the same thing happened to me :-) Amused the customer no end :-(

Many years ago I bought a rainwater diverter which was basically a piece of grey pipe with a 'T' connector and a raised outlet in the middle (as described elsewhere).

I didn't bother with connectors - just cut a hole in the side of the water butt (there was a recess for an incoming pipe) which was a snug fit for the pipe and pushed it in.

There is no pressure to contain (well, possibly 5mm head of water) so a fancy fitting isn't really required.

Never seeen one since, though, and have used RainSava (or similar) which require unblocking occasionally but do allow more flexible positioning of the water butt.

HTH

Dave R

Maybe I have missed something on this thread - but can anyone explain how these rainwater diverters actually work?

They appear to be a simple T juction with no moving parts, or valves. So why should rainwater, dribbling down all sides of the downpipe, elect to enter the water-butt and not continue to fall under gravity?

And what stops the butt overflowing when it is full?

DJ

I think they're more like the following:

from gutter

| | --+ | barrel | | --+ | | | 'cup' +--| |--+ | | | |

to drain

... there's a narrower small piece of vertical pipe in the middle. The rain mostly runs down the inside edges of the downspout and collects in the 'cup' section, where it's free to exit via the side pipe to the rain barrel.

So long as the top of the barrel is at the same level as the 'cup' then once the barrel's full, the 'cup' will also fill up, and excess water then spills through the narrow central pipe and from there to the drain.

cheers

Jules

OK - many thanks.

With your explanation above it does look feasible. It also explains why the pipe to the butt has to be fitted horizontally.

DJ

How tall is the "cup" section in most diverters? I would have expected the top of the narrow piece of pipe to be level with the top of the pipe to the barrel, which is roughly what your sketch shows. This would allow the whole bore of the pipe to the barrel to be used to carry water.

But the diverter I have seen in the shop today has the cup only half the height of the barrel outlet, which means the pipe can only ever be half full. Surely this is a wasted opportunity as the pipe can only ever carry water at half its capacity?

That's almost certainly true but remember that this type of diverter isn't very good at collecting 100% of the rainfall anyway and the percentage collected drops as the rainfall rate increases because it's only collecting from the wall of the downpipe so I don't think it's ever going to be limited by the bore of the connecting pipe.

Be aware their resistance to dead leaves is precisely zero

Is there a better type that collects nearer to 100% of the rainfall?

I thought all rain went down the sides of the pipe. I didn't think any went free fall down the middle?

My down pipe goes into the water butt and the overflow from the butt into the drain.

As I said in an earlier post I have one which collects all of the rainfall but it's old and I can't find them on sale anymore. Essentially it forces all of the rainfall into the butt and allows the butt to overflow back into the downpipe at about 1/2 bore (ie. a semicircle of 68mm pipe). All in one neat fitting.

During heavy rain there are two effects. One is that water will be cascading down the pipe away from the ways anyway but the other is that it's falling from, say, 4m so has considerable velocity. Don't expect all of it to be neatly caught by the internal lip and not bounce. Try fitting a short length of pipe to the top of a normal diverter and pouring a jug of water into it and see how much comes out of the side hole and how much out of the outgoing downpipe.

That sounds like a good idea, especially if you can arrange for the water to feed in at the bottom of the butt so that it keeps the content fresh rather than stagnant.

Has anyone DIYed a first flush system?

^^^^ Obvoiusly that should read "walls"

Yes mine goes to the bottom. I cut it at 45 deg to allow the water to escape and to cause it to circulate the water. You could fit a shoe on the bottom, I didn't have one handy.

I think that's what I'll do too. I think I'll set the bottom of the downspout a few inches* off the actual bottom of the barrel, then put a joint in the downspout just above the top of the barrel (which you also may have done) just so I can easily remove the barrel for cleaning every few years.

• I'm not sure if it'll gradually fill with sediment either, even with the circulation.

cheers

Jules