How to stop water backflow from stormwater kerb discharge.

[haitchb]

Hi all,

We moved in to our new home in October 2024 and I have noticed that after a downpour the ground near the stormwater discharge (at the kerb) is damp.

After some investigation, I have noticed the concrete (next to the road) has a slight lean back toward our house, which causes some of the water coming out of the discharge to flow back underneath the PVC pipe and into the nature strip. 

I extended the PVC pipe to encourage most of the water leaving the pipe to run into the drain. Although this has helped slightly, we still get dampness and I would like to fix this.

As digging up the road isn't an option, could I use a sealer or filler to stop the water flowing back into the nature strip? I've attached a couple of photos and have illustrated the water direction (in red), where the water collects (in blue) and where I would like to seal and stop the flow (in yellow).

  

Cheers,

Harry

[JacobZ]

Hi @haitchb,

A warm welcome to the Bunnings Workshop community and thank you for your question.

Realistically, having that little bit of water seep into the soil won't cause you any issues, so I question whether you need to do anything at all.

If you really want to, you can seal around the outside of the pipe with Sika Concrete Grey Sikaflex 11FC Purform but that would mean the water will just sit in the pipe, which could be a breeding ground for things like mosquitoes.

I imagine you'll want to put turf over this spot in the future. This will both conceal the dampness and benefit from this little bit of seepage. If it were my property, I would just leave it and lay turf over the top.

Allow me to tag @Jewelleryrescue, @Nailbag and @Dave-1 for their thoughts.

Jacob

[Dave-1]

Good Evening @haitchb 

Pretty much @JacobZ has taken the words straight out of my mouth. Your soil looks pretty dry to start with so any "free" moisture id welcome

However I do understand it could be frustrating, So I would cut your PVC pipe back to the exit in the gutter and then use the Sika that @JacobZ has suggested, I dont think the moisture inside the pipe will hang to long as the path does look warm. Just something to keep in mind

Dave

[Nailbag]

Hi @haitchb 

I agree with @JacobZ in that I wouldn't be concerned about the small amount of moisture and would be inclined to leave it as is. I would however be addressing the extended pipe well within the gutter, which now posses a danger that could see you liable for personal or vehicle damage. My recommendation would be to cut it parallel as per the green dotted line below.

Nailbag

[haitchb]

Hi all,

Appreciate all your input and advice on how to address this. It's definitely helped to ease some concerns I had, so I guess for now I shall wait until the rain arrives (which North of Adelaide isn't going to break any records!), and address the issue if needed. The nature strip is a concrete / dolomite mix on top of the pre-existing clay soil, so the majority of homes in the area do not touch it.

Thanks for the recommendation @Nailbag re: pipe. That's all been rectified now.

Cheers,

Harry

[Nailbag]

Nice one @haitchb 👌