For 40 years, National Water Service has been installing and servicing complex water systems in Homes, Restaurants, Hotels, Hospitals, Shopping Centers & more all over the DC, Baltimore & Frederick Metro areas. We work with Architects, Builders & Construction Firms to create custom applications for residential & commercial water treatment, purification, as well as a complete line of well pumps, boosters, etc. Whether on City Water or a Well System, water quality can vary quite a bit from street to street and we are happy to do a basic analysis of your water and/or existing water treatment at no charge. Our installers are all professionally trained in Water Treatment, Purification, Filtration and are certified well water specialists! and we offer the following Services : Well pressure tank & water treatment.