This research investigates a novel bio-based construction material combining components recovered from two major waste streams: sewage and soil. The potential of wastewater derived extracellular polymeric substances (EPS), commercially extracted as Kaumera, is explored as an alternative to cement based stabilisers for earth. The study evaluates the effects of EPS on the mechanical, durability, and aesthetic properties of compressed earth blocks through compressive strength and water resistance testing, as well as qualitative evaluation of surface characteristics. A research-through-making methodology was adopted, with assessment of multiple EPS formulations in both dry and gel form. Results demonstrate that gel-based EPS significantly improves water resistance and surface quality, while strength development remains highly sensitive to processing conditions. The research identifies EPS as a promising stabiliser, proposes potential architectural applications and provides a foundation for future development of circular materials derived from wastewater treatment as well as bio-based earthen construction materials.