A system for maintaining water quality in a water body having a surface area of at least 7,000 m 2 for recreational purposes, comprising: an excavated structure having a bottom and walls to contain the water body and a non-permeable flexible membrane covering the bottom of the water body, the bottom having a slope that is about 20% or less and the walls having a slope that is greater than about 45%; a chemical application system, wherein the chemical application system is configured for applying a flocculant to the water in the water body to maintain turbidity of the water below 2 NTU; a mobile suctioning device configured to moving along the bottom of the water body and suctioning a portion of water from the bottom containing settled solids, wherein the mobile suctioning device is configured to be activated before the increase in the bottom's color black component exceeds 30% on a CMYK scale; a filtration system including the suctioning device and a filtration unit, the filtration unit being in fluid communication with the mobile suctioning device, wherein the filtration unit is configured for receiving the portion of water suctioned by the mobile suction device; and a degreasing system, separate from the filtration unit, comprising: a separation unit comprising a degreaser and a screen or a coarse filter arranged and configured to retain large debris, wherein the degreaser is an overflow apparatus for separating oils and greases from water, and skimmers configured to skim the surface water of the water body 1, in fluid connection by a connecting line with the separation unit, wherein the degreasing system is configured to be activated to maintain a surface water layer having less than about 20 mg/L greases; one or more return lines configured for returning filtered water from the filtration unit and the degreasing system to the water body; and a control system comprising an automated system processing information, the control system being arranged and configured to receive information regarding water quality parameters, process the information, and activate the chemical application system, filtration unit and/or degreasing system to adjust the water quality parameters within their limits. an excavated structure having a bottom and walls to contain the water body and a non-permeable flexible membrane covering the bottom of the water body, the bottom having a slope that is about 20% or less and the walls having a slope that is greater than about 45%; a chemical application system, wherein the chemical application system is configured for applying a flocculant to the water in the water body to maintain turbidity of the water below 2 NTU; a mobile suctioning device configured to moving along the bottom of the water body and suctioning a portion of water from the bottom containing settled solids, wherein the mobile suctioning device is configured to be activated before the increase in the bottom's color black component exceeds 30% on a CMYK scale; a filtration system including the suctioning device and a filtration unit, the filtration unit being in fluid communication with the mobile suctioning device, wherein the filtration unit is configured for receiving the portion of water suctioned by the mobile suction device; and a degreasing system, separate from the filtration unit, comprising: a separation unit comprising a degreaser and a screen or a coarse filter arranged and configured to retain large debris, wherein the degreaser is an overflow apparatus for separating oils and greases from water, and skimmers configured to skim the surface water of the water body 1, in fluid connection by a connecting line with the separation unit, a separation unit comprising a degreaser and a screen or a coarse filter arranged and configured to retain large debris, wherein the degreaser is an overflow apparatus for separating oils and greases from water, and skimmers configured to skim the surface water of the water body 1, in fluid connection by a connecting line with the separation unit, wherein the degreasing system is configured to be activated to maintain a surface water layer having less than about 20 mg/L greases; one or more return lines configured for returning filtered water from the filtration unit and the degreasing system to the water body; and a control system comprising an automated system processing information, the control system being arranged and configured to receive information regarding water quality parameters, process the information, and activate the chemical application system, filtration unit and/or degreasing system to adjust the water quality parameters within their limits.