Harvesting Rainwater

[BlackAlys]

Planning on a few water butts at our new home but have thought about harvesting more rainwater.

Has anyone got a tank underneath their soil for doing this?

This was suggested to me when I had my garden done but I didn't want a pump, instead, I have 3 IBC tanks which aren't pretty but they work well.

We have 5 x 220 Litre waterbutts + 2 x 1000 Litre IBC Containers. We also have a disused below ground swimming pool which we use as a static water tank. The only pump we have is a 12v one which we run from a leisure battery and charged from a solar panel. This is used to lift water from the ex-pool to the waterbutts & IBCs when the get low (only needed once this year, despite being in East Anglia).
We find that gravity feed from the various water stores is enough to keep everything watered. We tend to water new plants twice weekly during their first season. Thereafter, unless it's really hot and they are showing signs of stress, they are left to fend for themselves.
Pots are watered 2/3 times week depending on rainfall.