Water is one of the primary demands for plant growth. The quality and quantity of produce are also directly linked to the nutritional value of the water. But with every system that water passes through, the environment acts upon it, changing its composition along the way. Within horticulture it all comes down to control of the growing environment. One of the important systems in controlling this environment, is a water purification system. It purifies the water enabling it for use in irrigation. The most common system used to date is a reverse osmosis system. The technology operates through pressing water through a membrane with minute pores. The unwanted substances stay one side of the membrane, while purified water comes out through the other side. Disadvantages of this technology is the unsustainable character, and high running and maintenance costs. This project is set up to find an alternative technology that does not have the disadvantages that RO systems have. Through extensive technology research capacitive deionization has been found to be the best suitable alternative for purifying water. It is an emerging technology that operates by removing the ions from the water, instead of removing the water from the ions (RO). Capacitive deionization technology is far more sustainable than RO. Electricity uses can be cut down up to 95% and chemical cleaning is needed much less than with RO. The technology is fully modular and allows for a wide range of operating characteristics, be it water recovery percentage or removal percentage. This report proposes a design that implements this technology and enables H2ollandWater (the company that offered this project) to compete with RO systems and distinguish themselves as an innovative brand. To date the technology is quite expensive, but it already allows a profit to be made over RO systems within 2-3 years of operation. Within the next few years, large CD modules will be developed, significantly lowering cost price and enabling H2ollandWater to compete in the market at a high level.