How to create charged wet system for house with mild negative slope?

[LorenClayton]

Hello

My house has a slight negative grade from the street. Front carport and roof gutter are connected to kerb. The 3 rear gutters need to connect to a wet, charged system also to kerb. Moreton Bay Council have approved this. They also recommended a drainage point so I can clean it out. Can you please provide a link to one of these?

I want to buy 4 Bunnings leaf eaters for my 4 downpipes (The $39.95 ones). I understand these help to prevent backflow of water up into the gutters and eaves and also backflow from the kerb.

I understand that a charged, wet system is prone to silt & sludge so how do I access the drainpipes to clean them? Are there easily accessible caps that unscrew? Can you please link to these if so? Or would this be part of the drainage point?

I'm not intending on having a water tank. Is the wet charged system OK with just drainpipes and leaf eaters, and regular maintenance to clear out the system? Please advise what I should be asking the plumber to install so I can do this. Also, should there be some sort of splash diverter for the water which splashes out next to the foundations during heavy rain? I'd rather this than a backflow back up my drainpipes, but excess water near the foundations isn't ideal either.

Also, a rear neighbour has a retaining wall behind the colorbond fence (see photo) and water pools up considerably. Should I install 2 groundwater pits either side in the back yard? Would appreciate some advice here as well.

Please advise the best system for me, preferably with a diagram. Thanks for your help.

site of wet charged system to kerb

[Dave-1]

Morning @LorenClayton 

Mmmmmm on the quiet I would ask a plumber if its allowed. I never like asking council (even tho mine is great ) becuase if they say no then its a really "solid" no in my head Think "wiggly hand" when sea sawing for an answer

Dave

[LorenClayton]

Hello again and thank you all for your patience in answering my questions (Eric & Dave, you're legends).

I have a house with a slight negative grade from the street, and Moreton Bay Council have approved the 3 rear drainpipes to go to kerb, with the suggestion:

" ... I note from your email that the proposed stormwater system is required to be charged given there is a slight fall from the kerb and channel to the rear of your property. Council recommends that the design of the system incorporates a method of draining the stormwater pipe in dry periods to ensure the water does not stagnate and become a breeding ground for mosquitoes or other parasites. This will also help reduce any buildup of material in the pipe which could block the pipe overtime."

What exactly should I ask for? Just to be clear, this system is just drainpipes with leaf eaters, and there is no water tank. 

Eric suggested before (a different post) that I get a Holman 100m female / female PVC DWV test opening (and yes, I'm getting this installed). He said this would allow me to hose the sludge out. Is this the same thing the council is asking for, or do I need something else as well?

Thanks very much.

[JacobZ]

Hi @LorenClayton,

I have combined this question with your original post as it will help provide context to our readers.

The inspection point @EricL has suggested can help with clearing out the pipe, but as they sit on top of the pipe, it is not what your council is referring to.

A charged stormwater system works by fully sealing the pipe, so pressure created by the water falling down the downpipes will push the water in the pipe uphill towards the curb. When the water level from the downpipes falls below the height of the curb, the pressure is no longer strong enough to push the water uphill, so it will sit stagnant in the pipe.

I believe your council is proposing you install a method of draining this water when the pressure is no longer strong enough to force water uphill. As gravity will cause the water to flow to the lowest point in the pipe, a valve at the lowest point of the stormwater pipe that can be opened when the rain has stopped is likely what your council is suggesting. I couldn't tell you an exact product to use, but a pressure-rated PVC ball valve is likely what your plumber will use. You'll have to speak with your plumber to ensure this is an appropriate method that won't leak when the system is "charged". 

It's likely worth following up with your local council to ensure this is what they mean. They will have dealt with this type of issue before, so they should be able to offer further details.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[LorenClayton]

Yes, I will check with Council what they mean. Thanks so much JacobZ.

[JacobZ]

No worries @LorenClayton,

I'd be interested to see what they say and whether my suggestion is in the ballpark of what they meant.

Let me know if there's anything else I can assist with moving forward.

Jacob

[LorenClayton]

Hello Jacob

Moreton Bay Council phoned me today in relation to this question. I don't think he really knew to be honest. At first he said it was a spur, but I've never come across this term before (a US term maybe?). Then he said it was a drain at the lowest point with a cap to unscrew. So can you please interpret that and tell me what you think he meant and maybe provide a link? Also, if an inspection point (if this is what it is) has a screw cap, is this a weakness in any way in that it might be liable to leak? Would the screw cap be facing up or facing down on the drainpipe? It's difficult finding information on this so thank you for your help.

[EricL]

Hello @LorenClayton 

The Holman 100mm Female And Female PVC DWV Test Opening can be sealed with an O ring to prevent air from escaping or keeping a vacum. But if your plumber says that it can't be installed in that section, then an inspection junction will need to be placed a bit of a distance away from the charged area. The inspection junction always faces upward, if you are after more technical information regarding pipework here is a link to the Holman PVC plumbing.

If you need further assistance, please let us know.

Eric