For 40 years, National Water Service has been installing and servicing complex water systems in Homes, Restaurants, Hotels, Hospitals, & 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, water heaters, etc. Our installers are professionally trained in Treatment, Purificatication and Filtration.