How to fix rainwater tank overflow without larger foundation?

GreenGrowth

Rainwater catchment is overflowing the storage tank during heavy rains even with the diverter active. The first flush is routing too much clean water away from storage. A larger tank would address capacity but the existing foundation may not handle the added weight.

cityseedling

The first flush pulling away usable water in heavy rain feels like the real bottleneck here. Is the diverter length adjustable at all, or does it run on a fixed volume?

waterwisewill

cityseedling nailed it on the first flush being the real loss point. Those setups are almost always fixed by the pipe length you run, so you’d have to swap sections if you want to change the volume. What volume does your local code actually call for on first flush?

GreenGrowth

It’s a fixed-volume diverter tied to the pipe length, so no adjustment without changing sections. Local code volume isn’t something I’ve checked yet.