You can find rain barrels and rain storage systems available in both above ground and below ground containers that can store up to 1200 gallons of nutrient rich rain water.
Rain barrels are designed both in half barrels to store up flush against the wall and full barrels that can be set to be free standing. If the need arises for additional rain storage these rain barrels are capable of interconnecting to allow storage into multiple rain barrels.
Now if the need arises for a lot more rain storage in one container you will find above ground and below ground rain storage systems that utilize motorized pumps to send out the water in a regulated stream under some extra pressure versus a simple gravity feed that is used in the rain barrel storage.
Whatever your needs may require you will find a great selection of practical, functional and very useful rain storage systems.