RWT involves a conformal planning unit, a robotic handpiece, and a console. This is a tissue-destructive technique that removes tissue by way of a waterjet, via one or multiple passes, to resect tissue and is commonly followed by a limited TURP to obtain hemostasis. This is typically performed under general anesthesia but also may be done under spinal anesthesia. The procedure involves utilization of a TRUS to help map the treatment plan and allows the urologist to preserve areas around the verumontanum. This verumontanum preservation area provides the ability to preserve ejaculation in a portion of men. The WATER trial was a multicenter, multinational trial conducted by 17 centers across the U.S., United Kingdom, Australia, and New Zealand.261, 268, 370-375 The trial recruited men 45-80 years of age with a prostate volume 30-80 cc and randomized them (2:1 ratio) to either the RWT or TURP groups. The initial trial had a primary outcome of changes in IPSS from baseline to six months (efficacy), but there are interim results published for one-year,372 two-years,370 and three-years post-treatment,371 as well as one year results for the U.S. group only,373 with the last follow-up data published five-years post-treatment. The mean improvements in IPSS and quality of life through one, two, three, and five years were similar between the RWT and TURP groups. There was improvement in Qmax with the 5-year data showing an improvement in both RWT and TURP (8.7 mL/s and 6.3 mL/s, respectively). The PVR improvement also remained durable at the 5-year mark, with improvements in both RWT and TURP (62 mL and 82 mL, respectively).261 While urinary complications and ≥Grade 2 adverse events were similar across groups, procedure-related anejaculation was less frequent for RWT compared to TURP (10% versus 36%; p=0.0003) at 6 months.268 Additionally, changes in Male Sexual Health Questionnaire Ejaculatory Dysfunction Short Form (MSHQ-EjD-SF) were an average of 2.7 points worse for TURP compared to RWT across the 5-year period (p=0.0015).261 Initial studies showed an increased risk of hemoglobin decrease in RWT compared to TURP. There have been multiple proposed methods to mitigate this risk of blood loss, including a proprietary catheter-tensioning device versus standard traction with limited TUR at the end of the ablation. Standard traction and limited TUR showed improved rates of hemoglobin decrease and transfusion risk compared to robust traction or standard traction alone, especially in medium and large prostates.376, 377  A separate subgroup analysis in men with prostates 50-80 cc who underwent RWT was performed, which showed a particularly robust reduction in total IPSS for RWT compared to TURP across all of the visits in all 5 years (-14.1 versus -10.8, respectively; p=0.02).261, 374  There has been data assessing the outcomes comparing one or more passes with the waterjet during RWT. Data has shown that patients who had two or more passes of the waterjet during their RWT had a significantly lower total IPSS (~4 points; p=0.0002) and quality of life scores (~0.7 points; p=0.0096) at 24 and 36 months compared to those who had one pass. Additionally, those who had two or more passes had a higher Qmax (~5 mL/s; p=0.0220) at 36 months, compared to those who only underwent one pass. There were no cases of bladder perforation between the patients that had one or more passes.378