How to add a new stormwater pit and connect to existing stormwater pipe?

[ppp]

I had lot of drainage issues in the backyard and this forum helped me to come to this stage so far. 

Now I'm planning to do entire project in couple of stages.
Stage 1) Adding a new storm water pit (300mm) and connecting it to existing 90mm storm water pipe in the ground. (Current Project)
Stage 2) Laying ag pipes in the ground and connect them to Storm water pit added in Stage 1(Later).

My to-do stuff is shown in this image- mentioned ag, pvc and storm water lines in the figure. 

* Pit to be used is Everhard 325mm Series 300 Shallow Stormwater Pit - Bunnings Australia

* Going to use pit boss Everhard EasyDRAIN Pit Boss Connector - Bunnings Australia to connect Storm water pit with Holman 90mm x 3m PVC Stormwater Pipe - Bunnings Australia to extend until existing storm water pipe in the ground. 

* And thinking to use this 45 degree T piece  Holman 90mm 45 degree Female To Female PVC Stormwater Junction - Bunnings Australia to connect new PVC with underground PVC pipe. 

* Also going to use Protek PVC Primer & Cement for connecting these pieces (I would like to connect all the pipes only with cement not with any flexible couplings) 

Do you guys have any other connector to suggest instead of 45-degree T piece?

If T piece is the right connector - can someone show me the steps involved to connect underground PVC ?

I see certain PVC connectors have threads - that means they are just connected without pvc cement: am I right?

And do all above mentioned PVC pipes/connectors are to be used in underground and above the ground right?

(I see bunnings product specification page shows inconsistent information related to *Underground rated* for these PVC connectors so confusing which one can be used underground, and which is not)

This is the underground PVC - I will have less room to work with

(Apologies for my rookie questions

[Jewelleryrescue]

Hi @ppp 

I dont think your area  warrantes a storm water  pit in the middle of  yard. Not enough area to collect huge water volume

I would run Ag pipes joining into  each other as they are flexable via y joins all the way to  storm water PVC pipe.  All under the  grass.

Ag pipe in proper sand and stone trenches .

Under ground  use the glue in fittings,  the screw infittings  tend to  be used in more major above ground water management systems for ease of access.

One  opinion only/

[MitchellMc]

Hi @ppp,

@Jewelleryrescue touched on a good point that a pit might not be necessary, and having all those connections terminating at the pit could cause issues. There's no need to run three separate aglines to the pit. The two at the lower area of your photo could be just a single length that the higher one connects into with a tee. The agline can then be joined to the stormwater with another tee and connector.

The 45-degree joiner is the correct product, and all the fittings are suitable for underground use.

Please be advised that this is considered drainage work and might require the services of a professional in your area.

Mitchell

[ppp]

@MitchellMc @Jewelleryrescue   Thank you for your suggestions, guys.

Even I felt those 3 ag pipes are bit too much for this area but having a pit is easy to maintain down the line, right?

If the ag pipes (even socked ones) are blocked with debris or soil, then I can clean them independently every couple of years also pit acts as a point to collect debris and soil before releasing it to storm water system.

If I connect all these directly to storm water system without pit, then I have no control over what goes in AG pipes right?

[MitchellMc]

Hi @ppp,

If you're happy with the pit in the middle, that is certainly an option to make access easier.

Mitchell