Using ACO drain for guttering downpipe?

[flanagaj]

We have a level threshold around the whole house and therefore we need to install ACO drainage.  As space is tight down the back of the property, I was wondering whether the downpipes from the guttering can feed into the ACO drain, instead of having to have a separate pipe system for the guttering downpipe.  The tech architect who did our drawings has drawn an ACO on one drawing, but then seems to have drawn standard underground 110mm pipe for the guttering.

[Russell griffiths]

What sort of pre filter / sump do you have before the rainwater tank. 
if you run acco drains into it it will be full of sediment in a short time. 
or is it on the drawing to keep someone happy. 

[flanagaj]

11 minutes ago, Russell griffiths said:

What sort of pre filter / sump do you have before the rainwater tank. 
if you run acco drains into it it will be full of sediment in a short time. 
or is it on the drawing to keep someone happy. 

I dont' think the TA even though about that 😞

A sump before the tank makes a lot of sense.  

 

[saveasteading]

Great to see a rainwater tank. What capacity? How will the water be used?

You can put a catchpit just before the tank and it will catch all the dirt. I put one in before a 10m3 tank and it never needed attention in the 15 years I had ownership. 

Catch the leaves before they get on the system.

100mm pipe has to stay. Aco can feed into it.

 

[flanagaj]

2 hours ago, saveasteading said:

Great to see a rainwater tank. What capacity? How will the water be used?

You can put a catchpit just before the tank and it will catch all the dirt. I put one in before a 10m3 tank and it never needed attention in the 15 years I had ownership. 

Catch the leaves before they get on the system.

100mm pipe has to stay. Aco can feed into it.

 

I still need to size it, but thinking 5000 litres.

[saveasteading]

That's a good size. It will catch and hold a big downpour, which is important in a dry spell. Depending on cost and space available, consider 2 smaller tanks.

I'm planning one now, and it will only be for garden watering. So I can't see a problem using a redundant plastic oil tank.... they are free from any heating plumber or on Facebook. The oil traces will be insignificant.

[flanagaj]

9 hours ago, saveasteading said:

That's a good size. It will catch and hold a big downpour, which is important in a dry spell. Depending on cost and space available, consider 2 smaller tanks.

I'm planning one now, and it will only be for garden watering. So I can't see a problem using a redundant plastic oil tank.... they are free from any heating plumber or on Facebook. The oil traces will be insignificant.

I also like the idea of a large tank as if the soakaway ever failed, I could simply fit a submersible pump into the tank and sneakily pump it out onto the road, which then flows down to a very large pond which always has loads of capacity.  Hoping it would never be required, but it's a useful backup.

[Alan Ambrose]

@saveasteading

 

I'm wondering how your rainwater plans are coming along as I'm just looking at this subject? For us, garden watering only and I'm wondering whether I can use a crate system like you would use for soakaways but surround it with DPC-like stuff so it mostly doesn't leak. We have a bunch of big pots planned and at our current place these are supplied by mains water and an irrigation system - works well but not inexpensive to run...

 

The kosher tanks seem crazily expensive?

Edited 4 hours ago by Alan Ambrose

[Alan Ambrose]

My analysis so far:

 

[Spinny]

We have 110mm pipe runs to the soakaway.

 

Will be installing one of these just before the soakaway to catch any silt which can then be periodically removed.

https://www.drainagepipe.co.uk/soakaway-silt-trap-c-w-catchpit-filter-with-lid-600mm-deep-x-300mm-diameter-p-SS300160LID/?keyword=&matchtype=&device=c&campaign=GS_|_Silt_Traps&gad_source=1&gad_campaignid=23172749930&gbraid=0AAAAADvEWfqWwSJceLuvN2RR_Gg15xZus&gclid=EAIaIQobChMIicj8z9rUlQMVRZFQBh3hHxguEAQYASABEgLB9_D_BwE

 

Unfortunately ours not complete yet.

 

Yes we will feed most of our groundwater from patio drainage etc into the soakaway. Still fitting gullies at the base of the downpipes though.

 

So how do you get the water out of an underground harvesting tank to water the garden then ?

 

 

[saveasteading]

Membrane is permeable so not appropriate.

Yes water tanks are expensive because they are for potable water and have to be strong.

For the garden you could use IBCs which are 1m3 and cost about £50 second hand. You can link them with tank connectors.

How to stop them crushing underground?  IBCs have the metal cage, so I'd wrap around that maybe with some old cladding or ply before backfilling.

[saveasteading]

On 18/02/2026 at 21:29, flanagaj said:

large tank as if the soakaway ever failed, I could simply fit a submersible pump into the tank and sneakily pump it out onto the road.

That sounds naughty but is better than just letting the soakaway fail.

In reality you are holding back exceptional water which is a good thing.

Use it for the garden or pump it back into the soakaway in summer.