  We study possible ways gravitational waves (GW) are sourced in a theory with
minimal left-right symmetry breaking. Generically first order phase transitions
(FOPT) lead to gravitational waves sourced by bubble collisions, while second
order phase transitions (SOPT) do not. However, due the presence of two
degenerate fields, we obtain domain walls in the putative SOPT case, giving
rise to GW via decaying domain walls, testable at experiments such as IPTA,
DECIGO, and LISA. On the other hand, for the case of FOPT, we get the usual
signal from spontaneously created bubbles, but also a late forming domain wall
structure separating the two types of vacua. Thus the traditional FOPT case
gives rise to two distinct peaks in the spectrum of GW, verifiable for the low
symmetry breaking scales $10^4 - 10^6$ GeV, but beyond the reach of currently
planned experiments for a high scale $\sim10^{10}$ GeV. Finally, we point out
that a version of the left-right symmetric model which separates parity
breaking from gauge symmetry breaking is also subject to domain wall formation
and amenable to GW observations.
