  Over the past decade, parity-time ($\mathcal{PT}$)-symmetric Hamiltonians
have been experimentally realized in classical, optical settings with balanced
gain and loss, or in quantum systems with localized loss. In both realizations,
the $\mathcal{PT}$-symmetry breaking transition occurs at the exceptional point
of the non-Hermitian Hamiltonian, where its eigenvalues and the corresponding
eigenvectors both coincide. Here, we show that in lossy systems, the
$\mathcal{PT}$ transition is a phenomenon that broadly occurs without an
attendant exceptional point, and is driven by the potential asymmetry between
the neutral and the lossy regions. With experimentally realizable quantum
models in mind, we investigate dimer and trimer waveguide configurations with
one lossy waveguide. We validate the tight-binding model results by using the
beam propagation method analysis. Our results pave a robust way toward studying
the interplay between passive $\mathcal{PT}$ transitions and quantum effects in
dissipative photonic configurations.
