Water companies face increasing challenges in achieving the progressively lower phosphorus discharge limits required to protect receiving waters from eutrophication. These limits, often in the range of 0.15–0.5 mg/L in AMP8, demand treatment performance approaching the boundaries of current technology. Achieving such low concentrations is complicated by the variability of influent wastewater characteristics, fluctuations in flow, and the need for highly reliable chemical dosing, monitoring, robust chemical supply and sludge management processes. Conventional technologies become more costly and challenging at ultra‑low targets, while advanced technologies introduce additional operational complexity and maintenance demands. Financial pressures, embodied carbon considerations, and tightening regulatory expectations further constrain feasible solutions. As a result, water companies must balance innovation, affordability, resilience, and environmental outcomes. This necessitates integrated adoption of robust monitoring and control systems, and a shift toward more adaptive, energy‑efficient, and sustainable phosphorus removal strategies. Thames Water assessed the performance of standard phosphorus‑removal technologies implemented at existing sites where low‑phosphorus limits were introduced during AMP6 and AMP7. The review covered a range of solutions, including chemical dosing combined with pilecloth filters, high-rate ballasted processes, reed beds and sand filters, across both trickling filter and activated sludge (ASP) treatment plants.