This investigation pertains to the evaluation of water quality in SAWA Lake, located in the Al-Muthanna province of Southern Iraq, from 1977 to 2020. Understanding the water quality and assessments of this Lake is of great importance. The Lake is home to small, transparent, blind fish measuring approximately 10 cm and is often referred to as the "wonderful" or "strange" Lake due to its many unique features. The study focuses on several elements to represent water quality, including total dissolved solids (TDS), electrical conductivity (EC), pH, and temperature (T), which were measured directly in the field. Additionally, scientific concepts such as K⁺, Ca²⁺, Cl^-, HCO₃, and KSO₄ were used in each sample. Scientists have analyzed the density and salinity of the lake water and found that its water density exceeds that of seawater, and its salinity exceeds that of the Gulf of Arabia by about 1.5 times. The water is salty, surrounded by natural lime, and is automatically renewed by nature when it is broken. Its hardness also characterizes it, and its water volume fluctuates depending on the wet and dry seasons. The Lake is roughly 4.74 km in length, and all the elements under study showed an increase in concentration during the periods of 1977, 1983, and 2003 with NaSO₄, which later changed to MgCl between 2007 and 2011. The study found that Sawa Lake water was unsuitable for drinking or irrigation purposes between 2016 and 2020 due to the increased concentration of certain elements. This increase in concentration is attributed to the Lake's location, nutrition, and the lack of rain, which means it relies solely on groundwater.