POOL BACKWASH ADAPTER JUNCTION

In Australia, most plumbing codes require swimming pool backwash to be directed to a stormwater system.  Typically these comprise 90mm plastic (PVC) pipe, while the pool system is a 40mm pressure pipe.

I could not believe that there is no adapter for this purpose, so installations end up looking a bit like a dog's breakfast, with multiple “Y's” and reducers stacked (refer photo)  - this model has a 48.5mm internal diameter for the nominal 40mm pipe connection, and a 90.8 ID for the top (IN) 90mm rainwater pipe, with an 86.8 mm diameter for the bottom (male) connector.

The model pictured is printed in PETG, and will be painted to protect it from UV.   It's quite a light print, but has stood up well to its intended purpose for several months at this stage.

I would welcome feedback if anyone finds this useful, and am happy to customise the pipe sizes on request.