If the leak is allowed to continue, water damage can appear on the inner face of the wall and this can create the ideal conditions for wet and dry rots to take hold.
Os na wnewch rywbeth am y gollyngiad, gall difrod dŵr ymddangos ar wyneb mewnol y wal a gall hyn greu amodau delfrydol i bydredd gwlyb a sych ddatblygu.