Consistent high quality pre-treatment of the feed water is one of the most important prerequisites for long-term successful operation of seawater desalination plants. A first step to fulfill this requirement is the use of directed drilled horizontal drains below the sea bed, a technology that has been developed by drilling experts based on experiences with dredge-less pipeline installations starting 1996. With the use of these horizontal drains the raw and fine screening, as well as conventional filtration of seawater will not be necessary due to the fact, that the sand of the sea bed will act as a "natural" pre-filter, separating all kind of solids and particles down to the micron range from the seawater to be fed to the desalination plant. This system, introduced as Neodren, can be operated in sandy and karstic sea beds as ecological and economical alternative for conventional open seawater intake systems and has even advantages in comparison with beach well installations. This technology for seawater intake and pretreatment can also be adapted successfully in areas with high contaminated seawater. It minimizes the environmental impact and is safe against the destroying forces of waves in the coast line. It is applicable for desalination plants for the production of drinking water from seawater on any scale between several 100 ml/d to several 100,000 ml/d. In combination with micro-bubble flotation and ultrafiltration the process minimizes drastically the need for chemicals that are necessary usually for the pre-treatment of seawater in order to reduce the scaling and fouling potential and to prevent biofouling before feeding it for example to blocking-sensitive membrane elements of a reverse osmosis plant. Reduction of the costs related with infrastructure, logistics and operation can be achieved.