The horizontal sand filters made with polyester resin and winding glass fiber can be applied to the water filtration in public pools, aquatic parks, irrigation water and water treatment in general. They provide a great surface area for filtration with a limited space and very economic costs. Manual or automatic valve batteries are available with 3” to 8” depending on the filtration rate required. The standard models of horizontal filters can work under pressure 2.5 bars or 4 bars. Custom-made horizontal filters can be made if required and possible.