Advice on burying stormwater pipe

[trover]

I would also suggest a drain point for a wet system, to drain out the dust every now and then. Thats a screw on lid on a tee piece, of instead of an elbow. Good luck with the digging.

[Vernonv]

Trover - yeah I was planning to do that at the point where the pipe goes "up" to the water tank inlet. I will use a T piece with a screw fitting on one end of the T bar.

Bricks - I'm not quite sure I understand why I would want to use 65mm downpipe (I'm sure I'm missing something here). Wouldn't it be better to use the biggest possible pipe size - I was planning on using 90mm from a leafbeater down to 100 sewer for underground and then 90 back up the the tank inlet.

[bricks]

What I'm getting at is that if your changing from stormwater grade to pvc grade pipe your going to have to buy an adaptor, If you keep all the pipe grade type the same eg all Pvc then you will be able to use available fittings to connect your down pipes to the system.

Everytime you change pipe it will have a small cost associated with it.
Every time you change its another fitting that you need to install neatly to look nice- not easy if you don't have much room.

65 pvc might be okay, but whoever sold you the shed / roof should be able to give you the correct size for your area.

If your going to a large pipe size for the down pipes i'd use 100mm pvc as it (more often than not) is cheaper than 80mm pvc. Pvc is thicker and therefore won't be damaged as easily by things hitting it. you will need to paint the pvc to prevent it from becoming brittle in the sun.

Or you could bring up 100 pvc to about 250mm above flood level and then run a standard square down pipe into it, That way you won't need a fitting at all. You would need to ensure the pvc is raised to above the outlet of the stormwater system.

To make a long story short.......

Install a downpipe of any material
Lay the 100mm sewer grade pipe as you were going to,
Bring up 100mm risers where the down pipes are,
Run to tank as needed,
Make sure the downpipes have stopped above the level of the inlet of the tank, and that the 100 pvc over-laps by about 50mm.

This way if the system does ever block up between the tank and the gutter the overflow will be from the downpipes around the outside of the house, not the gutters and back into your shed / house.

Hope that helps,

[Vernonv]

Thanks Bricks, that clarifies things.

Also thanks for the additional info - I hadn't really considered what would happen if things blocked up.

[bricks]

No worries bloke, I just hope you realise im not the best communicator with the written word, hoping im not coming off as an arrogant know it all.

Let us know how it goes anyways

Cheers.

[Vernonv]

Bricks, I haven't taken the delivery of any of your comments, suggestions or information as being arrogant. And greatly I appreciate your input, as well as that of the other contributors.

I let you know how I get on (with pics, hopefully), but it may be a while as it will take approx 2 months to get the tanks (must be all these Sydney people buying water tanks and pushing up demand).