# Forum Home Renovation Plumbing  Stormwater Pits

## an3_bolt

I am putting 100mm PVC pipe through a 300 x 300 x 300 stormwater pit as part of our runoff from the front of the house. I was planning on using a hard plastic pit (everhard) or alternatively a slightly larger GRC pit (glass reinforced concrete).
Has anyone had any expertise with these?
Are there standard methods or acceptable practice for joining the PVC pipe to the pit (ie simply silicon etc)?
Any advice that can be passed on with regards to stormwater and pits?
Thanks

----------


## bricks

Ferropre or mega poxy, this will do the trick.
Available at your local plumbing store, or most hardware stores.

----------


## journeyman Mick

Don't forget to fill the bottom of the pit with concrete up to the bottom of the outlet pipe to stop water sitting there and mossies breeding. 
Mick

----------


## Bleedin Thumb

> Don't forget to fill the bottom of the pit with concrete up to the bottom of the outlet pipe to stop water sitting there and mossies breeding. 
> Mick

  This seems to be the norm nowdays, but I was always taught that you had to keep the invert of the outlet pipe higher than the floor to act as a sediment trap. IE you had to clean them out every so often but you were preventing the sediment from entering the SW. :Confused:  There seems to have been a change in philosophy? Whats the reg's say? 
AFA the pits go...only bother with the reinforced ones if your going to drive over them...otherwise plastic is fine. I find an easy way to cut the hole is to heat up an old knife till its glowing....its then like cutting butter.

----------


## wonderplumb

Ive gone off using ferro to seal pipes into plastic pits as Ive found that over time it comes away from the plastic so I use sikaflex instead. The everhard pit will be fine and more than likely cheaper aswell as easier to work with. Wether or not you choose to bench the pit (concrete the bottom to the same invert as the outlet) is up to you, unless council or some hydraulic engineering wiz has stated you go one way or the other.

----------


## an3_bolt

Firstly - thank you for the replys - all help is appreciated and has helped greatly. 
Just a quick query: 
If I provide a concrete benching to outlet level - won't the concrete simply seperate from the plastic and end up cracking over time? Do you simply use concrete and that is that? 
Also is there a minimum fall between the inlet and outlet pipes?  
I have found the Everhard - seems to suit the application that I am after ie a non-trafficable area. The diagrams I have indicate benching to the outlet. 
Cheers

----------


## journeyman Mick

> This seems to be the norm nowdays, but I was always taught that you had to keep the invert of the outlet pipe higher than the floor to act as a sediment trap. IE you had to clean them out every so often but you were preventing the sediment from entering the SW. There seems to have been a change in philosophy? Whats the reg's say?..........

  This may just be a local/regional thing. It's to stop the mossies breeding. We have a dengue fever outbreak at the moment with about 600 confirmed cases (might be more by now) and one fatality.  
Mick

----------


## Bloss

Very much local - in the ACT if you altered the design as described they would not pass it . . .

----------


## an3_bolt

Just to follow up in case any one else needs the info as have obtained manufacturers instructions: 
Instructions include positioning on a bed of compacted bedding sand, pipes through wall should be sealed with a suitable silicon based adhesive/sealant. Benching should be conducted with a pour of mass concrete up to the invert of the lowest pipe. Exterior mass concrete should be poured around pipe exits outside the pipe to provide pipe support. If mechanical reinforcement is required of pipe connection to pit - instructions advise to use stainless bolts and washers with a flange to pit exterior wall and suitable sealant with adhesive qualities. 
Cheers

----------


## wonderplumb

Basically install the pit and pipework, I usually sparge them on quickset concrete or sand and cement after Ive fiddled around levelling it, sikaflex or silicone around the pipes both inside and outside the pit, then mix a nice runny mix of quickset concrete and pour it in the bottom till it matches the invert of the pipe, smooth off and backfill.

----------


## Bleedin Thumb

Well it looks like filling with concrete is the go then, I'd still be interested what the water authorities say about it though.

----------


## intertd6

I  think any authority would be concerned about standing water, because when mixed with vegetable & animal matter it can become septic & produce noxious gases which are heavier than air, which then accumulate in stormwater systems in down stream pipes & a risk to the public & workers.
regards inter

----------


## bricks

More often than not they are concerned with preventing those types of rubbish entering the stormwater system. 
It really does depend on who your talking too.

----------

