High-quality single crystals of ${\mathrm{\text{Bi}}}_2{\mathrm{\text{WO}}}_6$ are grown using a flux method. With different flux growth recipes, we aim to control the crystallization temperature to be lower and higher than the ferroelectric transition temperature, resulting in mono-domain and multi-domain ${\mathrm{\text{Bi}}}_2{\mathrm{\text{WO}}}_6$ crystals, respectively. Abundant ferroelastic orthorhombic twin domains are observed in the multi-domain crystals under an optical microscope. PFM studies unveil the 90${}^{\circ }$ polarization change across those ferroelastic domain walls, as well as the absence of 180${}^{\circ }$ ferroelectric domains in the as-grown multi-domain crystals, indicating a high energy cost of 180${}^{\circ }$ ferroelectric domains. Moreover, a 45${}^{\circ }$ tilt of the 90${}^{\circ }$ ferroelectric domain walls is discovered, and this tilt creates a new type of charged 90${}^{\circ }$ ferroelectric walls, which have not been observed in other bulk ferroelectrics.