The article discusses the fundamental aspects of the water deficit problem in rural areas of the South Prydniprovska Upland, which is prevalent in the Mykolaiv, Cherkasy, Kirovohrad, and Dnipro regions. The study focuses on the rapid hydrochemical instability observed in locally accumulated runoff reservoirs, significantly deteriorating their water quality for consumer use. The inherently high salinity, exacerbated during peak water shortage periods, diminishes the significance of local hydrosystems as viable water sources. The swift advancement of autonomous filtration water treatment systems and artificial filtration in drinking water production necessitates a reevaluation of traditional principles in rural water supply. Concurrently, this development brings to light several critical technical issues with economic implications. Cost-effective decentralized water treatment for drinking purposes mandates the use of natural water with a salinity of up to 1.5-1.8 thousand mg/dm3. Treating water with a salinity of 3-4 thousand mg/dm3 would be economically unfeasible due to the need for accelerated replacement of filter elements, excessive electricity consumption, and extended working hours. Therefore, the challenge of accessing water reserves with minimal deviation in hydrochemical composition from drinking standards persists, as current reservoirs and water storage facilities do not meet this requirement. To rationally exploit available water reserves, the proposed principle of cascade-separate water use for small reservoirs is introduced. This approach is based on creating a tandem of existing channel ponds and small water storage reservoirs linked by regulated water flow. The satellite water storage ponds, filled from the surface with relatively clean, flotation-deposited water from the main pond, will contain a 3-4 month supply of conditionally high-quality water, ensuring efficient operation of drinking water treatment plants at a volume of up to 20 m3/day. These relatively small (up to 0.5 million m3) reservoirs are easy to maintain, clean, and periodically disinfect, meeting the minimum water quality requirements for preparation for drinking and the domestic needs of the population.