Image credit: M. Kornmesser/ESO
The seven planets of the TRAPPIST-1 system, confirmed to exist by Belgian astronomers in 2017, turn out to possibly have 5% of water in their rocky crust. This represents an amount 250 times as large as Earth, and as such the system has enough water to possibly support life.
For more on the discovery of water:
(https://www.space.com/41714-water-rich-exoplanets-trappist-1-system.html)
For more on the idea that water world can support life without requiring to be an exact simile of the Earth:
(https://phys.org/news/2018-08-worlds-life-analysis-idea-requires.html)